Who Is to Blame for the Decline of Large Housing Estates? An Exploration of Socio-Demographic and Ethnic Change

In the 1960s and 1970s, all over Europe housing estates emerged that were very similar with respect to construction methods and urban design. At the same time, housing estates across Europe did not all follow the same trajectory after their completion. This divergence occurred because the main reasons for their deterioration and social degradation are exogenous factors, not internal factors. Of course, it makes a difference whether the physical quality of the dwellings was good and whether the spatial planning was adequate. But even well-designed housing estates are subject to social degradation due to competition with newer neighbourhoods that are usually added at the top of the market and more geared to contemporary housing preferences. In Western Europe, this process of relative depreciation is further exacerbated by the prioritisation of owner-occupation leading to residualisation of the social rented sector. The social and ethnic transformation of large housing estates is not only the consequence of planning and housing policies but also of external factors like immigration and economic decline. Most European countries have witnessed a substantial in ﬂ ow of immigrants in the pre-vious decades, and many of these ﬁ nd their way to large housing estates. Next to that, the social decline of housing estates is often related to a shrinking local economy. Policies aimed at reversing the decline hurt the sitting population more often than it helped them.


Introduction
Inevitably, the large housing estates that were built in earlier decades now suffer from the competition of newly built dwellings. In many cases, newer dwellings are of a higher quality and can also be more attractive in terms of location, which seduces those households who can afford it to move to this new housing stock, leaving less attractive estates behind for those who do not have the financial means to move to attractive new dwellings and places.
This process of social transformation often goes hand in hand with ethnic transformation. In many European cities, more and more newcomers in large housing estates are from an ethnic minority background. This is due to the increasing diversification of cities as a consequence of immigration. Moreover, immigrants and their descendants are disproportionally distributed over urban space and are most likely to end up in a neighbourhood with a relatively weak position in the urban housing market.
This chapter focuses on the causes of the changing social and ethnic profile of housing estates and will offer explanations for the variations in this process across European cities. According to Hoogvliet and Hooimeijer (1988), the dynamics in population composition of neighbourhoods depends mainly on four factors: (1) The original situation: Many physical characteristics of a neighbourhood, like dwelling types, urban design, and physical quality, as well as its relative location have been fixed from the time of realisation. New neighbourhoods are usually different from the existing housing stock as they are built to address the needs of housing seekers that cannot be satisfied by the existing stock. Post-war housing estates were built to solve the enormous housing shortage after World War II, which was caused by a combination of demolition and low new housing production during the war and high population growth. Although the emphasis was more on the production of quantity than of quality, moving to a housing estate was a major improvement for those who left inner-city slum areas.
(2) Relative depreciation: In many theories of neighbourhood change, the concept of filtering has a central place (van Beckhoven et al. 2009). The general idea is that as dwelling units grow old, they tend to depreciate. This is not only due to physical deterioration or obsolescence but also relative depreciation. Even if neighbourhoods remain in good condition, they will have more and more trouble over time competing with new neighbourhoods that are usually added to the market at the top of the quality and price hierarchy and are more geared to contemporary housing preferences. Therefore, dwellings and neighbourhoods filter from higher status to lower status populations. The construction of new homes starts a chain of residential moves. This creates the filtering of households up the housing scale and consequently the filtering of dwellings (that is, estates) down the social scale.
(3) The management of the housing stock: The pace of relative depreciation is to some extent determined by how the housing estate is managed. Management comprises a wide range of activities, including maintenance of dwellings and public spaces, housing allocation policies and mediation in case of tensions between neighbours. (4) Renewal and reappraisal: Downgrading of a neighbourhood can be reversed by processes of renewal. These processes of renewal may be more or less spontaneous and led by private actors, like in the many western inner-city neighbourhoods that were the target of gentrification, but renewal processes in post-war housing estates were usually characterised by a more direct involvement of the (local) government.
These four factors form the structure of this chapter. Additionally, the role of macro developments, like immigration and economic restructuring, are discussed. While the tendency in most literature about neighbourhood decay is to look for explanations within the dynamics of a neighbourhood, the role of external factors should not be underestimated (Grigsby et al. 1987;Murie et al. 2003). Turkington et al. (2004) identify a wide range of problems (to be discussed in the next sections) that high-rise estates across Europe are confronted with. While most of these problems have an impact on the functioning of high-rise estates in the longer term, poor design and inadequate planning may lead to a spiral of decline very soon after the completion of the estates.

Poor Physical Design
Many estates malfunctioned from the beginning due to physical shortcomings: elevators were too few and often did not work, there were problems with waste disposal systems and with condensation and leaking, and many high rises had bad acoustics (De Decker and Newton 2009;Hall 2014).
Of course, not all high-rise housing estates had the same physical problems. There are differences in the quality of construction within countries, between countries and between different time periods. In the UK, for instance, there was a substantial difference in the quality of design between London on the one hand and the rest of England and Scotland on the other hand. In London, top architects took the lead in the design of large housing estates, whereas elsewhere architects had to work within the strict requirements of housing departments, which were mainly focused on realising the maximum number of units in the minimum possible time (Glendinning and Muthesius 1994). In Eastern Europe, the quality of design tends to be lower than in Western Europe, mainly for economic reasons (Kährik and Tammaru 2010;Monclús and Díez Medina 2016).

Weaknesses in Urban Design and Inadequate Spatial Planning
One of the planning flaws of many large housing estates was that they were located on the fringes of cities, far away from any amenities and job opportunities. Functions like schooling, shopping and recreational opportunities were underdeveloped (De Decker and Newton 2009). In Southern European housing estates, the public transport connections to the rest of the city are often underdeveloped (Dekker and Van Kempen 2004). Peripheral locations were chosen to reduce costs. For instance, Quarto Cagnino in Milan (1964Milan ( -1973 was built as 'marginal appendix to the city', as the legal framework limited the development of public housing estates to the availability of less expensive plots of land (Monclús and Díez Medina 2016, p. 542). Another shortcoming of the modernist housing estates is that their monotony stands in the way of the residents' need to express their lifestyle and to acquire their status through their dwelling. De Decker and Newton (2009) criticise Le Corbusier for the ignorance of the symbolic meaning of housing. To Le Corbusier, a house was une machine à habiter, designed to serve the function of a dwelling and nothing more. However, people have the need to show who they are through their homes. The extreme standardisation of the modernist housing estate does not facilitate its appropriation by the new inhabitants. This standardisation tends to be the most problematic in the largest housing estates. The 'drab monotony' in Eastern Europe is even more extreme than in Western Europe (Monclús and Díez Medina 2016). In Western Europe, large-scale projects like Sarcelles at the outskirts of Paris or the Bijlmer in Amsterdam are faced with extreme standardisation. In Gran San Blas in Madrid (1958Madrid ( -1963, the largest housing estate of the period in Spain, monotony was avoided by dividing the district into neighbourhood units. A considerable variation between the units was created, as the designs varied in the degree of sticking to modernist prescriptions, as documented in the Athens Charter (Monclús and Díez Medina 2016). Hall (2014) argues that Le Corbusier, as well as his followers, had no real feeling for the way of life of working-class families. The famous housing complex Unité in Marseille, designed by Le Corbusier himself, is a completely different world compared to the British council tower blocks or the French grand ensembles. That is not so much due to the quality of the design, which in Hall's view makes the complex resemble 'a medium-quality hotel', but due to the fact that it is occupied by middle-class professionals. For working-class families, the suburbs offer great advantages in terms of privacy and freedom from noise. There, they have their own garden where they can relax and where their children can play safely. Hall (2014) concludes that high-rise estates may work well for rich people, due to the access to high-quality services and the amount of time they spend outside their homes, but that these kinds of places are not fit for working-class families.
Modernist housing estates are also criticised for the negative impacts of the built environment on social life. Research in Scotland revealed high-rise estates score worse than other areas in social and psychosocial outcomes, like frequency of contact with neighbours and a number of aspects of (perceived) control (Kearns et al. 2012). The design of space in many large-scale housing estates was often too fluid and open with no well-defined spaces and no clear hierarchy. There was a lack of attention for the connection of common space and private space. Residents did not feel responsible for public spaces, which soon became desolated and dilapidated (Monclús and Díez Medina 2016). Oscar Newman (1972) uses the term indefensible space to describe the discouraging effect of physical design of these estates on collective community actions, which makes these neighbourhoods susceptible to crime.
Newman has been criticised for his architecturally deterministic position, but nevertheless his ideas have been adopted in Europe. Alice Coleman argues in her book Utopia on Trial (1985) that the design of high-rise public housing estates is responsible for anti-social behaviour. Although her ideas have not been taken seriously in academic circles, her work had a high impact on housing policy in the UK. Her critique of modernist architecture was compatible with the neoliberal agenda of Thatcher's government  and-as we shall see later-Thatcher's policy has led to the depreciation of council housing estates (Jacobs and Lees 2013).

Recruitment of Initial Residents
The problematic start of some housing estates is in several cases not only due to the poor quality and design of the buildings and the environment but also to the recruitment of the first residents. Van Kempen and Musterd (1991) compared several ill-functioning and well-functioning post-war housing estates in two middle-sized Dutch cities. The differences between these estates could not be attributed to physical and management characteristics. Instead, the initial population composition appeared to be crucial for the performance of the high-rise blocks. Estates where the poverty level was already high among the initial population experienced a process of decline very soon after the estate was built. The problem is not only that poor people have more problems in paying their rent but also that the concentration of poverty led to a bad reputation among outsiders (Murie et al. 2003).
Some housing estates in Western Europe also faced an influx of immigrants. When the Bijlmer (1968)(1969)(1970)(1971)(1972)(1973)(1974)(1975) in Amsterdam was completed, the expected influx of residents from within the city did not materialise. Families in the older parts of the city did not consider the Bijlmer as a suitable environment to raise their children (which is in line with Peter Hall's point of view discussed above) and opted for neighbourhoods in the new towns and suburbs outside Amsterdam. The huge number of vacancies were filled to a large extent by immigrants from Surinam who left their country in the period around the independence of this former Dutch colony (Aalbers 2011).
In former communist countries, the initial population of housing estates had a different ethnic and socio-economic profile. While housing estates in Western Europe were mainly inhabited by blue-collar workers and immigrants, housing estates in Eastern Europe were dominated by the middle class. In Hungary, for instance, there was much less equality in housing allocation than what might be expected from a communist state. Bureaucrats, intellectuals, the military and workers in high-priority sectors were over-represented in the state-built housing estates, whilst members of the working class often had to rely on the self-build housing sector (Herfert et al. 2013). This allocation policy leads to a spatial division between the cities and their hinterland, with a much stronger presence of people with a high level of education and income in the former than in the latter (Kährik and Tammaru 2010).
In several Eastern European countries, like Hungary and the Czech Republic, some housing estates carried a bad reputation due to the policy to segregate Roma (Temelová et al. 2011;Váradi and Virág 2014). For instance, the Roma ghetto of Chanov, located at the edge of the city of Most in northern Bohemia (Czech Republic), was a housing estate constructed on the city periphery with the aim to accommodate the Roma population, which was displaced as the consequence of the opening of a coal mine. Chanov was a stigmatised neighbourhood from the onset and was avoided not only by the Czech population but also by better-off Roma (Temelová et al. 2011).
In most of Central and Eastern Europe, large housing estates did not see an inflow of immigrants. In the 1990s, some countries attracted guest workers from other socialist countries, but the numbers were much lower than in Western Europe. At the end of the 1980s, 50,000 foreign citizens were working in Czechoslovakia, including about 35,000 Vietnamese and 5,000 Cubans. In Bulgaria (40,000 guest workers), the majority came from Vietnam (Grečic 1991). The German Democratic Republic (the former East Germany) hosted more than 100,000 guest workers, with Vietnamese again forming the largest group (59,000), followed by immigrants from Poland and Mozambique. These guest workers did not get access to state housing estates but were housed in hostels where they were excluded from German Democratic Republic society (Dennis 2007). Most of them were forced to leave immediately after the political upheaval in 1989/1990.
With respect to immigration, the countries of the former Soviet Union have a distinct history. In Kazakhstan (Gentile and Tammaru 2006) and the Baltic states (Kährik and Tammaru 2010), there is a considerable amount of segregation between the native population and the large number of Russian-speaking immigrants. These immigrants, who arrived through organised channels, tended to be housed in the new panel housing districts. In contrast to the Western European situation, these immigrants did not live in worse housing conditions (and in some cities even in better housing conditions) compared to the native population.

Relative Depreciation
Relative depreciation refers to the decline of social status in neighbourhoods due to competition with newly built neighbourhoods. The size of the housing stock, characteristics of the local housing market and tenure distribution play a role in the depreciation of a large housing estate.

Size of the Housing Stock
In Western Europe, the scale of large housing estates is seen as one of the reasons that these areas are degrading. A comparison of Oslo and Stockholm, two cities situated in countries with strong welfare states, reveals that income segregation is much higher in the latter city. Whereas Oslo did not build a huge amount of multifamily public housing and dispersed these projects in small pockets over the city, Stockholm chose for large-scale public housing estates which since the Million Homes Programme (from the mid-1960s to the mid-1970s) cover many suburban areas (Musterd et al. 2017). This concentration led, in combination with the residualisation of public housing, to an accumulation of lower income groups and non-Western immigrants in these estates.
Whereas the concentration of public housing in large housing estates is seen as one of the factors explaining the social downgrading in Western Europe, the sheer size of large housing estates in post-socialist cities will ensure these neighbourhoods will never be seen as places to exclusively house the poor. Large housing estates provide 30-50% of the urban housing stock, as opposed to at the most 10% in Western European cities (Herfert et al. 2013;Grossmann et al. 2017;Murie et al. 2003). As a consequence, large housing estates as a whole have never been stigmatised in Eastern Europe. Many middle-income households live in a large housing estate and almost everyone will have family and friends that live in the same or similar housing estates. Surveys in Leipzig and Prague revealed that housing estates are still considered as an ideal residential environment by a wide range of households (Grossmann et al. 2017).

Characteristics of Local Housing Markets
The competitive position of large housing estates depends on the pressure on the local housing market. Van Gent (2010) compared four housing estates in Birmingham, Amsterdam, Barcelona and Stockholm. Although the four neighbourhoods were similar in their urban design, Birmingham was much more stigmatised as a slum area. Residents there are seen by outsiders as people that only stay there because they have no choice to move to a better place. The other three housing estates could benefit from spillover demand due to high pressure on the regional housing market.
High pressure on housing markets can be alleviated by new housing production. In segregation literature, it is often overlooked that this can be a factor that exacerbates the spatial division between the rich and the poor. In Dutch cities, post-war housing estates face tough competition from greenfield developments built at the edges of the big cities. These developments attract middle-and high-income households, many of whom move out of the relatively deprived housing estates. This resulted in an increasing concentration of low-income people in post-war housing estates. The spatial division between the rich and the poor is increasing in all six cities that were investigated, but the trend was strongest in cities where greenfield developments were the most extensive (Bolt and van Kempen 2013).
The lack of new housing production was one of the reasons that large housing estates in Eastern Europe did not end up in a downward spiral after the collapse of communism. Herfert et al. (2013) compared large housing estates in five Eastern European cities (Leipzig, St. Petersburg, Sofia, Budapest and Vilnius) and found that the housing shortage became more severe in the 1990s due to a lack of new construction. The only exception was Leipzig, where outmigration to the western part of Germany led to an oversupply at the large housing estates. The lack of new housing production, combined with the deterioration of the inner city (especially in St. Petersburg and Sofia) meant that the competitive position of large housing estates remained quite good. In two cities, St. Petersburg and Sofia, the socio-economic composition in the large housing estates does not differ from the inner city. In the other three cities, however, there is a tendency of a growing socio-economic segregation and a declining social status of social housing estates.
Riga (Latvia) and Tallinn (Estonia) also did not experience a sharp increase in residential segregation in the first decade after the transition (Musterd et al. 2017). Like in other post-socialist countries, rapidly increasing income inequality did not translate into spatial divisions (Marcińczak et al. 2015). Again, this is partly due to the lack of new housing. However, in the second decade after the transition, new housing kept up with the demand. New housing was mainly built in suburban areas and aimed at the better-off. This led to increasing socio-economic segregation, which in the case of Tallinn was also amplified by ethnic divisions (Musterd et al. 2017). Although both Riga and Tallinn have a very large Russian-speaking community, Estonians are much more segregated from the Russian-speaking minority than Latvians. Compared to the situation in Riga, members of the Russian minority are much more concentrated at the bottom of the social hierarchy and they are also more clustered in large housing estates from the socialist period. The better-off Estonian-speaking residents tend to leave these estates and move into suburban areas that are dominated by members of their own group.

Tenure
Ownership structures of large housing estates differ between the various parts of Europe (Dekker and Van Kempen 2004). In Southern and Eastern Europe, owner-occupation is most prevalent, while most dwellings in large housing estates in Western and Northern Europe can be found in the social rented sector. Due to the dominance of owner-occupation in most Southern European housing estates, the residential turnover is lower than in Northern and Western Europe and, consequently, the pace of social degradation is also slower (Turkington et al. 2004). In Italy, however, some social housing estates were built in the 1970s. Neighbourhoods like Vele in Naples and Corviale in Rome have experienced rapid social degradation, suffering from a high rate of school drop-outs and the infiltration of mafia (Boeri and Longo 2012).
Owner-occupation in Eastern Europe has become prevalent since the transition, which led to a privatisation of the housing market. It took some time for financial markets to adapt to the new situation leading to limited access to mortgage credit. Combined with the low level of new housing production, this resulted in a low level of mobility in the first decade after the transition (Herfert et al. 2013;Musterd et al. 2017).
In Western and Northern Europe, where the share of social rented dwellings is much higher, a distinction can be made between a universalist approach, which emphasises provision for all households, and a dual approach focused on the provision for lower income households (Scanlon et al. 2015). In a dual system, social housing is more marginalised and therefore it seems reasonable to expect that the level of segregation will be higher than in a universal system (Arbaci 2007). However, Skifter Andersen et al. (2016) show that the opposite applies for Nordic countries. Copenhagen and Stockholm operate within a universal housing system, but the social housing estates are characterised by high concentrations of immigrants. In Oslo and Helsinki, access to social housing is restricted to the lowest-income households. However, the concentration of immigrants in this sector does not lead to high levels of segregation. In Oslo, the social housing sector is very small and spatially dispersed, and in Helsinki social housing is much more mixed with other tenures than in Copenhagen and Stockholm. Apparently, the size and the spatial distribution of the social/public sector are more important determinants of segregation than the type of approach used. In Copenhagen and Stockholm, the public sector is accessible for all income groups, but the concentration of these dwellings on large housing estates engenders a high concentration of immigrants.
Within Western and Northern Europe, there is a trend towards a residualisation of the social rented sector. Residualisation is the trend that the social rented sector gradually becomes the exclusive domain of low-income households (Bolt and van Kempen 2013). The term first appeared in UK, where the social rented sector has declined due to privileging of the owner-occupied sector (Murie et al. 2003). The introduction of the Right-to-Buy Act in 1980 led to a decline in the share of social rented households from 31% in 1981to 19% in 2012in England (Fenton et al. 2013. As economic incentives are much larger to buy in popular areas (where the gap between buy-out price and value was much bigger), the proportion of social rented dwellings in large housing estates remains relatively high and the proportion of low incomes is increasing due to a lack of affordable alternatives. In large housing estates where social dwellings are sold, the effects on the neighbourhood tend to be negative. Permentier et al. (2013) performed a large-scale evaluation of the selling off of social housing in the Netherlands and found a positive effect on livability indicators (like social cohesion and safety) only for higher status neighbourhoods. In low-status neighbourhoods, the effects were negative. In Bijlmer, for instance, a housing association decided to terminate their selling project, as too many sold dwellings were sublet to other people and/or used for criminal activities.
In London, the Right-to-Buy Act led (in combination with other policies strengthening the commodification of housing) to the dispersion and suburbanisation of the urban poor over the 2000s (Fenton et al. 2013). The same trend can be seen in Stockholm, although the Right-to-Buy policy there is more recent. Between 1990 and 2010, the proportion of public housing declined from 32 to 18% and the decline was even sharper in the inner city (from 19 to 7%). This resulted in a residualisation process in the multifamily outer suburbs (where large housing estates dominate the housing stock). In 1990, the income distribution there was very similar to Stockholm as a whole: 21% of residents were in the lowest disposable income quintile. By 2010, this number had risen to 32% while the proportion of non-western immigrants grew from 17 to 47%. In Stockholm as a whole, the growth (from 6 to 16%) was much more moderate (Andersson and Turner 2014).

Management
According to Glendinning and Muthesius (1994), the majority of high-rise blocks are attractive places to live with good management. The problem is that many housing estates are faced with flaws in management, both in terms of maintenance and housing allocation.

Maintenance
The maintenance budgets of large housing estates tend to be too limited, especially in Eastern Europe (Murie et al. 2003). In Tallinn, Estonia, for instance, the lack of resources for the maintenance of the housing stock led to significant deterioration over time (Kährik and Tammaru 2010). The privatisation process in Eastern Europe did not automatically improve the maintenance of large housing estates. While investment in renovation and maintenance increased in better-off neighbourhoods, new homeowners in lower status neighbourhoods often could not afford the necessary maintenance costs. This led to further physical degradation (and as a consequence also a social degradation) in the latter areas (Temelová et al. 2011).
Lack of maintenance is not a typically Eastern European issue but a problem that can be found all across Europe. In Sant Roc (an estate in the Barcelona region dominated by owner-occupation), for example, the housing stock is in a dismal state due to minimal investments in maintenance (Van Gent 2010) and the same applies to social housing estates such as Vele in Naples (Vele) and Corviale in Rome (Boeri and Longo 2012). In Glasgow, large housing estates have to cope with a harsh climate on top of the limited resources for maintenance. Wet weather conditions led to problems with dampness and water penetration, which would not have occurred if the same buildings would have been located in other parts of Europe (Kearns et al. 2012).

Housing Allocation
According to Kenneth and Forrest (2003, p. 51), it was in part the '… active exclusion of the poorest or those deemed to be less deserving which gave the social housing of the early post-war period its social status'. In the course of time, however, the social profile of incoming tenants started to change in countries like the Netherlands (Van Kempen 2000) and Britain (Goodchild and Cole 2001). In the popular imagination, large housing estates are nowadays seen as concentrated enclaves of poor people (Kennett and Forrest 2003). The timing of social degradation is very much dependent on the regional housing context. Problems started in the 20-storey John Russell Court block in Edinburgh only 5 or 10 years after the opening in 1964 when problem families were moved in, which quickly led to the deterioration of the image of the estate (Hall 2014). The reason for this change in allocation policy was the housing surplus that occurred in the UK at the end of the 1960s, which was the result of the 1960s production 'success' in building unprecedented numbers of new dwellings (Glendinning and Muthesius 1994, p. 320).
As explained above, the housing allocation process was completely different in Eastern Europe. The intellectual, cultural and political had better access to the housing estates at the most desirable locations (in the central cities), which meant that the socialist society was much less egalitarian than what could be expected on the basis of the dominant ideology (Kährik and Tammaru 2010;Kovács and Herfert 2012). After the transition, the differences in social status between more and less desirable locations have increased.

Renewal
As explained in the introduction, Hoogvliet and Hooimeijer (1988) mentioned renewal as the fourth factor (next to the original situation, relative depreciation and management) that impacts the population composition of the neighbourhood. In Western Europe, there is strong involvement of the (local) state in the renewal of high-rise estates. This renewal is aimed at attracting middle-class residents by transforming tenure structure. Social transformation policies tend to be most radical in neighbourhoods where most dwellings are in the hands of the municipality or housing associations. Van Gent (2010) found in his comparison of four housing estates that in Barcelona (Sant Roc), social transformation was least drastic, as most residents were owner-occupiers and therefore had a quite strong bargaining position. They were granted the right to be relocated within the neighbourhood after the demolition of their dwelling. In Stockholm (Tensta), a failed attempt was made to change the social composition by the privatisation of part of the housing stock in the late 1990s. Large-scale restructuring was not an option in Stockholm, as the Swedish policy framework does not cover the costs of the demolition of municipal dwellings. In Amsterdam (Bijlmer) and Birmingham (Central Estates), where most dwellings were social rented, the restructuring of the housing stock was much more focused on changing the socio-economic profile of the population.
In the Netherlands, neighbourhoods with a high proportion of dwellings built in the post-war period (1945 to 1970) and a high proportion of low-income households are most likely to be targeted for large-scale restructuring. While targeting poor neighbourhoods is consistent with a philosophy of creating more social mix, it is perhaps surprising that the ethnic composition of a neighbourhood also seems to play a role in the targeting of neighbourhoods. Even when housing stock characteristics and the proportion of low-income households are controlled for, the proportion of members of minority ethnic groups is a strong predictor for the probability of an intervention aimed at replacement of social housing by owner-occupied homes (Permentier et al. 2013). Although changing the ethnic composition of the neighbourhood is not part of the formal policy, there are many indications that it is no coincidence that immigrant-dense neighbourhoods have a high chance to be targeted. A policymaker in Amsterdam, quoted by Van Gent (2010, pp. 73-74), argues 'We are diluting problems and by doing so making them more manageable. … This means that if you have 80% immigrants (in a neighbourhood) and you lower it to 60 or 40%, the problem will be easier to manage'. This is certainly not unique for the Dutch situation. For instance, one of the motives for the regeneration of Sant Roc in Barcelona is the policymakers fear of 'ghettoisation' and the negative consequences of the concentration of immigrants for the housing prices in the area (Van Gent 2010), and in Montreuil (France) the high proportion of immigrants is considered a problem by a local planners as it supposedly presents a bad image (Kipfer 2016).
In France, redevelopment has a disproportionate effect on immigrants as renewal projects are predominantly located in Zones Urbaines Sensibles which tend to be areas with high concentrations of immigrants and their descendants. To Kipfer (2016), social mixing is not only racialised in terms of targeting immigrant-dense areas but also in the practices of the allocation of social housing. Responsible commissions are biased in their attempts to prevent the recreation of 'ghettos' or the concentration of 'large families'.
In the Scottish context, the ethnic composition of the neighbourhood is much less of an issue (due to their lesser presence) than in France, but also here housing estates are stigmatised on the basis of the population composition. Estates like Craigmillar in Edinburgh (Kallin and Slater 2014) and Glasgow's East End (Gray and Mooney 2011) are defamed by media and politicians, because of the concentration of poverty and the pathological effects (like criminality and the culture of poverty) that are believed to result from this concentration. The territorial stigmatisation in British cities is connected to the residualisation of public housing discussed before. The stimulation of home ownership and the Right-to-Buy policy has led to normalising ownership and delegitimising council housing (Kallin and Slater 2014). In combination with an allocation policy which located the most deprived tenants in the most deprived estates, it can be argued that it is the state that has created the 'concentrated poverty' that it laments.

Population Change
Within Europe, there are large differences with regard to the proportion of immigrants in the population. In 2014, foreign-born people accounted for 10.2% of the total population in the EU (Eurostat 2015). Roughly two-thirds came from outside an EU member state. The seven EU member states where the foreign-born population accounted for less than 5% of the total population are all post-socialist countries: Lithuania, Hungary, the Czech Republic, Slovakia, Poland, Bulgaria and Romania. In Southern Europe, the proportion of immigrants is slightly above (Spain, Greece) or below (Italy, Portugal) the EU average, while Western European countries have a higher than average proportion of immigrants (with the exception of Denmark). Estonia and Latvia are the post-socialist countries with the highest proportion of immigrants (most of whom are born in Russia), but these countries face emigration, like most Eastern European countries, while Western European countries experience a migration surplus (Musterd et al. 2017).
Immigrants tend to move to large cities, and within these cities they are often concentrated in large housing estates. In Amsterdam, about 80% of the population of Bijlmer has a non-Dutch ethnicity (Aalbers 2011). Tensta, a housing estate at the periphery of Stockholm, is one of the areas that suffered from the Right-to-Buy policy. It was stigmatised more and more and is increasingly avoided by native Swedish households; 85% of residents are foreign-born (Van Gent 2010).
In Athens, there is a low level of segregation of immigrants, which can be attributed to the absence of large housing estates. In the 1990s, Athens experienced a substantial inflow of immigrants (Albanians being the largest group), but they were relatively evenly dispersed over the central areas if Athens. Most immigrants moved into affordable low-quality apartments in neighbourhoods around the city centre (Maloutas 2016).
On the basis of a comparison of the four Nordic capital cities, Skifter Andersen et al. (2016) suggests that the degree of segregation is linked to the level of immigration. The level of segregation appears to be highest in Stockholm, which has the largest immigrant population, while segregation in Helsinki (with the smallest immigrant population) is lowest. This may be explained by a stronger tendency for 'white flight and avoidance' in the context of a large immigrant population (see also Andersson and Hedman 2016).

Declining Employment
One of the reasons that the heydays of large housing estates in Western Europe were relatively short-lived was that they very soon got a bad reputation among the public (Hall 2014;Turkington et al. 2004). The disastrous collapse of Ronan Point (an East London tower block) in 1968 as a consequence of a gas explosion and the demolition of Pruitt-Igoe in 1972 received a lot of media attention. Pruitt-Igoe was an American modernist public housing estate in St. Louis, Missouri completed in 1956. Physical deterioration, rent arrears and vacancy rates of 30% led to the decision to raze the entire complex. Hall (2014) comes up with the usual suspects to explain the failure of Pruitt-Igoe: poor physical quality, indefensible space leading to vandalism and criminality, lack of maintenance, and the admission of poor (black) family households.
The Pruitt-Igoe Myth, a 2011 (Freidrichs 2011) documentary film, argues that most explanations focus too much on internal factors. The social downgrading of the Pruitt-Igoe complex should be seen as a result of the economic restructuring of St. Louis. Pruitt-Igoe was a declining housing estate in a declining region. Employment opportunities were shrinking, and incomes were declining. As a consequence, renters were getting poorer and often could not pay their rents anymore. As a consequence, the funds available for maintenance and security of the buildings were reduced.
The story of Pruitt-Igoe has been replicated in European cities many times. The decline of the Park Hill housing project in Sheffield (1954Sheffield ( -1961, which initially was one of the most praised public housing schemes of the post-war period, can be explained to a large extent by the collapse of the steel industry (Monclús and Díez Medina 2016). Craigmillar in Edinburg suffered from the closure of local breweries, the creamery and the coal pits (Kallin and Slater 2014). In Malmö (Sweden), poor neighbourhoods suffered much more from the economic recession in the early 1990s than other neighbourhoods. This led to sharp increases in both income inequality and income segregation (Andersson and Hedman 2016). This underlines that not only selective mobility but also in situ change plays a large role in segregation trends. In segregation literature, there is much more attention for the former process than for the latter. Temelová et al. (2011) also argue that, in the case of Czech housing estates, the decline in socio-economic status in situ is equally important as an explaining factor for social degradation as the inflow of poor people from outside to the housing estates. This in situ decline in socio-economic status is intertwined with the ageing process, since the elderly generally become poorer.
Some Eastern European housing estates suffered even more from the deindustrialisation process than their western counterparts. In contrast to the rest of Europe, new cities were constructed at sites where new factories emerged. When factories closed, these cities were abandoned, as they were too dependent on a single employer (Monclús and Díez Medina 2016).

Conclusion
In the traditional literature on neighbourhood decline, neighbourhood trajectories are portrayed as a natural, apolitical process. All neighbourhoods are supposed to go through a certain life cycle in which the number and order of the different stages are fixed (van Beckhoven et al. 2009). Although life cycle theories are not supported in academic circles anymore, policy documents still present the decline of housing estates as the outcome of 'inevitable processes of impersonal quasi-natural forces' (Gray and Mooney 2011, p. 11). Nothing could be further from the truth. There is nothing natural about neighbourhood decline. The decline of neighbourhoods is the outcome of economic forces and of political decisions. The concentration of poor households in housing estates is the result of political choices with regard to (among others) the planning of new neighbourhoods, the prioritisation of homeownership and austerity measures. Even the stigmatisation that often goes hand in hand with the social and ethnic transformation of housing estates is partly produced by state actors. The rationale for creating a worse reputation is that it widens the rent gap (opportunity for profit), which facilitates state-led gentrification focused on displacing the poor to make space for the middle class (Kallin and Slater 2014).
State-led gentrification may lead to an upgrading of a neighbourhood, but it will not help the residents of housing estates and it will not reduce the level of segregation within the city as displaced households tend to move to other poor neighbourhoods. What is needed is a new kind of housing policy which does not prioritise homeownership over renting. Social housing should not be residualised and stigmatised. Paris and Zurich set good examples here as they plan to expand the social sector in more expensive neighbourhoods (Bolt 2017). Converting social rented dwellings to owner-occupation should be restricted as it leads to a higher socio-economic as well as ethnic segregation (Boterman and Gent 2014), as shown in the Amsterdam case. New housing should preferably be built within existing cities. Building new housing at greenfield locations not only has ecological disadvantages but also leads to higher levels of segregation (Bolt and van Kempen 2013). Paradoxically, many high-rise housing estates are characterised by low density and offer plenty of opportunities for new housing projects which do not necessarily lead to the displacement of the sitting population.
With regard to interventions within housing estates, the focus should be on people rather than on the built environment. Stimulating social cohesion would help to create more stability in these areas. Of course, this policy has a physical aspect (creating meeting opportunities), but it is mainly about recognising the value of bottom-up efforts in the community. The numerous initiatives that exist in large housing estates can play an important role in the support of marginalised groups and contribute to social cohesion. Policymakers could support local initiatives financially and should stimulate the cooperation between these initiatives. Furthermore, policymakers should focus on increasing the social mobility of sitting residents. Language courses for immigrants and educational programmes for people with a low level of education could help people to find a job. Moreover, residents could be encouraged to start new firms through offering micro-credits and counselling. Rather than trying to attract the middle class, in situ upward mobility would be the best way forward to reverse social decline.