1 Introduction

Green spaces are natural ornaments for environmental security and sustainability in urban areas [1]. These spaces are taken into account for environmental services to improve the quality of life in the cities and ecosystem services. Un planned urban development affecting the beauty of the earth’s surface and the environment as a result the local ecosystem becoming extremely harsh [2] causing increase in Land Surface Temperature and deforestation. As s result the ultraviolet rays are directly fall on earth surface and affect the human body along, other skin diseases. Therefore, the green spaces in forms of parks, trees or trees belt are necessary in congested urban infrastructure [3]. This greenery provides the security to the earth from water erosion and make the environment naturally cool along other ecosystem services [4]. Improving the urban life quality, green spaces provide a platform for recreation, reduce mental stress, depression and control environmental threats such as air and noise pollution coming from vehicles and industrial smoke etc. [5]. The studies proved that the parks and green infrastructure provide natural amenity to the local resident. This is evident that, the area with green infrastructure has a good quality of life with good environmental conditions [6].

Green infrastructure in urban areas in the form of parks, green belts, trees, trees belts, and plants, enhances the value of local atmospheric conditions in terms of neighborhood services [7]. Urban green spaces such as lawns, kitchen gardens, trees along a road or path, and urban forests provide valuable ecosystem services against pollution sources created by human and their activities [8]. In the world, a large ratio of the population is moving to urban areas along migration. They built a miss balanced and miss management between environmental and construction policies by increasing the built-up areas with massive urbanization. On the other hand, the high ratio of consumed resources by the urban population adds pollution and emits harmful gases that also contribute to climate change in urban areas, cause smog and global warming, and destroyed the scale of of green areas [9]. The green spaces also called urban lungs as they contribute and ensure the urban life quality as examined by [10]. According to previous studies associated with urban ecosystem, parks and urban green infrastructure, the overall urban infrastructure of cities can be improved by shady trees, flora, grassy lawns, plantation and green spaces [11,12,13].

However, in case of developing nations the urban built-up structure degrate the environment and ecosystem along with destruction of green spaces at a geographical scale. Therefore a dire need is to develop more green spaces and plantations in congested areas of the urban world to provide ecosystem services and environmental sustainability to the locals. This study makes an attempt to investigate the distribution of urban green spaces and parks in mega city with densely populated area, the extant of green vegetation by calculating Normalized Difference Vegetation Index (NDVI) for quantification of green extant. For estimating the environmental justice, the study examines the distribution of parks and total population density in term of per person green area over the total population and access to urban green. This social prospective was investigated by applying the Multiple Linear Regression Model (MLRM) by keeping the availability of park/urban green in area as dependent variable and accessibility to parks, total distance from their residency or house, frequency of visit was taken, as independent variables. The resultant analysis shows that according to international standards, per capita green spaces are less in the Town, of Lahore. This imbalance provision of environmental services is a challenging task, for policymakers and a hurdle for urban sustainability.

Around the world it is observed that the urban ecosystem become very harsh by domestic, industrial, transportation, fuel burning, which also causes social injustice by degrading the environment as indicated by [14] in most of the developing world. The study concluded that there is a dire need for research in developing nations on such crucial issues to gain sustainability and resilience, along with improving the urban life quality, and the study will provide documented proof to ensure urban justice in terms of the provision of environmental services and human well-being in forms of urban green for sustainability.

1.1 Urban green and the world

The green spaces and parks in an urban area provide recreational and aesthetic values to urban dwellers, and visitors as visual comfort in an environmental context [15]. Green space is defined as an unsealed piece of land consisting of soil, grass, trees, and shrubs, especially in an area with a permeable piece of land [1]. However, grassland, urban parks, and densely ray of trees are considered urban green infrastructure. All these spaces are under the umbrella of the same category, which may or may not be managed publicly in the developing world and need attention for their existence because the government gets failed to manage them in a better way. Various studies on green spaces shows their positive reflection on human society in different dimensions including leisure, recreation, entertainment, and increase of sales market values of property in economic terms [16]. Here, the sales values mean to assign a value in money to properties that have a green infrastructure in nearby areas [17]. The cities are growing nowadays, which needs to be planned and designed for the allocation of green spaces for sustainable development [18]. Another important benefit provided by urban green spaces is the socio-environmental aspect through which urban green provides a platform for social gathering in a societal context [19]. The social gathering in the sense when people get free from their daily secludes visit the parks, open spaces, or gathered during the other social events which create social mental harmony among them. This social gathering creates a social interaction, particularly in older citizens which makes their health better and creates an environment of well-being socially [20].

1.2 Biodiversity and green infrastructure

The green infrastructure provides lot of cultural ecosystem services such as biodiversity in city areas, landscape services, playgrounds for children, open spaces for local cultural events, and much more [21]. In addition, they assist and facilitate health and well-being by providing platform for physical activity, space for accelerated social interaction, and neighborhood coherence. Every individual can benefit from urban green space interferences. However, it could be of unique opportunity for socially deprived or underserved neighborhood population [22].

In the world, more than 50% of the population has been living in town, which is very crucial to manage the distribution of natural resources in equal ways [23]. Biologically, green spaces reduce the emission of industries, and the amount of CO2 in the atmosphere enhance biodiversity and improve the local ecosystem [24]. The social perspective of green spaces provides ecological resources to ensure the urban life quality and living infrastructure. Modern studies show that green spaces provide a platform for outdoor activities to urbanities, the psychological effect including aesthetic values and economic means, green spaces contributed to positive deflation in property prices values. For sustainable development, decision-makers, urban planners, ecologists, economists, and political authorities should make parallel decisions in economic, social, planning, and developmental patterns for regional sustainability and development.

1.3 Spatial structure of green spaces

The spatial structure of green spaces is very important for city dwellers and urban land use planning [25]. Initially, understanding the concepts of "eco-city", a sustainable city" which is a green city required more attention that emphasizes green spaces for environmental services. The range of user, visitor’s magnitude, and ownership of green spaces and their management forms and mage the infrastructure and mechanism of green areas. The green spaces contributed potentially to urban renewal and enhancement of the local environment. The environmental enhancement not only makes the places stronger but also strengthen the local economy and local environmental quality [26]. This makes a potential on local land and property values [27]. The institutional infra is very important, the institutes manage, arrange, and ensure the quality of green spaces for the local community and visitors. The unified divisional structure ensures the delivery of all services together for the public to overcome issues faced by green spaces.

The strategic management of green spaces requires the action of government and local community involvement which strengthens the structure and maintain the green infrastructure. The involvement of the local community increases the sense of ownership, increases business, and promotes communication. The population who visit green spaces may divide into two major groups, users and non-user where, the user may be defined as people who visit green spaces frequently while the non-user are those who visit green parks rarely in a time gage [28]. However, potential research is still required to recognize the voluntary inputs regarding their services for environmental justice.

In urban planning, the question "Where green space is located" is very important for the planner and urban ecologist, for a sustainable approach and environmental justice. Environmental justice means provision of environmental justice including green areas, parks and biodiversity near to a residency. This provision is associate with approachability, access to green area, proximity to a park at a walkable distance. That’s why approachability to green spaces is very important, especially in this current era of busy life, associability provides a way through which people have easy access to green areas and visit them frequently [29]. Nowadays all around the world even in densely populated areas such as in case of Lahore where the urbanization rate is very high from few decades, urban green areas including natural green, or parks face several problems through natural and manmade activities such as climate change, air pollution, population pressure, lack of planning, management and poor infrastructure of existing parks [30]. One of the major problems found in developing countries is the non-availability of funds and finance for the maintenance of green infrastructure, and this problem is a crucial problem that has been identified during the review of the literature of this study in previous research and official reports. These official reports include the Local Government of Punjab, the Lahore Development Authority, and the Municipal Corporation of Lahore.

2 Methods and materials

2.1 Study area

This research study has been conducted in Shahdara Town, Lahore. The town is situated in the middle of the city, with a congested population network. This town is situated near to the bank of the Ravi River providing the best location and making it ideal for a home of biodiversity [31].

The current population of the Town is 188,196 inhabitants [32]. However, the migration rate is very high in this area due to the construction of new housing colonies and the population is moving towards the area from nearby rural areas [33, 34]. This issue creates hurdles for environmental services (green spaces, parks, playing grounds) provisions and their distribution in this area. The study used two types of green spaces including formal (formal-GS) and informal green spaces (informal-GS). Haji Lal Deen and Tomb of Jhangir and Asin Khan are informal green spaces while all other parks are formal green spaces. Figure 1 shows the map of the area under investigation along with the location of green spaces, residential community, and the location of houses.

Fig. 1
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Source: Author (2023)

Map of Study Area, Shahdara Town, Lahore.

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2.2 Data acquisition and analysis

Two types of data were collected including GIS data and the data associated with green spaces in the town for social analyses. This data was provided by the Statistical Bureau of Punjab to check the association between population growth and availability of green infrastructure according to world's standards (see the Fig. 2), whereas data on green spaces regarding their location, distribution in the town, and their category, collected from parks and horticulture policies documents for 2017 from Government of Punjab. GIS data obtained from United States Geological Survey (USGS) website. This GIS data was analyzed through ArcGIS 10.3.1 software for spatial analysis (measurement of NDVI, and area calculation). Population growth data of the town was overlaid on the layer of green spaces in GIS environment. The map of the study area shows the relation between the ratio of population growth and green space availability in the area at a walkable distance. This relation is taken as spatial analyses. It has been investigated that due to more distance from the residential areas people avoid to visit them frequently, and number of parks are less and population is more which put pressure on natural resources and existing green infrastructure gradually. The following Table 1 shows the green area distributions in the town.

Fig. 2
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Source: Author (2023)

Population distribution and green spaces in Shahdara Town.

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Table 1 Area distribution of Green Spaces in Shahdara town.
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Above Table 1 shows the total area covered by each green spaces or parks present in the town. According to these calculations total area covered by green infrastructure is 1,350,360 ft2 square while the total area of the town is 116,305,200 ft2. According to world standards, this ratio is very less and the population is growing at a very fast rate. These issues will lead to environmental injustice for future generations in terms of the unavailability of green areas and parks which also threaten the urban life quality. This comparison was made to check the scale of environmental justice for urban planning and resources management.

Approximately, 1/3 area of the town is under barren land. The private housing societies developed the residential colonies and housing for settlement. Above Table 2 provide the land distributions of environmental services to check the social justice in term of neighborhood services. Due to unplanned residential infrastructure, green spaces have been vanished. Existing green spaces are threaten because of the high amount of industrial fossil fuel and climate change. That is why, public health facing different environmental dangerous hazards.

Table 2 Land distribution and area of green spaces in Shahdara town.
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2.3 Data analysis

The exact locations of the parks, roadside green spaces, man-made forests, home lawns, and gardens are taken through GPS point data and the detailed information map is drawn through ArcGIS 10.3.1 by GPS collected data. After conducting all data from the field, personal observation and results of in-depth interviews were analyzed in statistical form through Multiple Linear Regression Analysis (MLRA). The data collected from the interviews from the residents of the town were analyzed through SPSS for statistical techniques including Multiple Linear Regression Model and their results were expressed through the value of “R” and R square as coefficient of regression and power of explanatory.

Geographical information system and statistical analysis data are evaluated and results were presented in the form of NDVI maps and regression summary. The techniques of remote sensing and geographic information system (GIS) use to detect the level of urban growth, and availability of green areas in every section of the total area as shown in Fig. 2. In Fig. 2 the study shows the green areas/parks in green dots and the population of that area with numerical values and represent in different colors. For NDVI data from Land sat-8 (TM) were collected from the United States Geological Survey (USGS) website. The resulting map is then digitized and imported into a GIS (Geographic Information System) environment using ArcGIS 10.3.1 software, for NDVI calculation. For statistical investigation, Multiple Regression Analysis was done by using the variables including the green spaces in the town and the population (their access to green areas, distance from the houses and their frequency of visit) in the area. This test was used to check and scale out the level of environmental justice in the town by comparing the total population of the town and green space availability. Finally, discussion and conclusion were made by keeping the objectives of the study with results to provide the evidence base results for environmental justice and, urban sustainability in the area, even for the developing world.

3 Results

The results of the study show the quality and quantity of green spaces in terms of their area and green vegetation index (NDVI) in terms of urban biodiversity in the town. Green spaces like residential lawns and parks square considered a necessary part of life as ecological balance. These spaces measure the basic part of the property setting as investigated in the study area. Parks and open spaces are playing an important role in balancing the natural flow of energy and nutrient cycle and also as social platforms for people gathering and playing grounds for children. They also provides natural habitats to the organisms that have a very fruitful impact on health and improve urban biodiversity. Further, they also give several social, economic, and health related advantages. They have a positive impact on life quality as proved by [35] and the same case is investigated by the study.

Table 3 shows the outcome of the regression model according to data “R” value 0.844 representing a positive relation between dependent (location of green space) and independent variables (people access, distance from their house to parks, and their monthly income) related to residents of the inhabitants in the study area. It also observed that the local inhabitants of the study area have sufficient income, absence of knowledge of green spaces and their importance for environment stability. Similarly, the "R Square” value (0.883) describes the coefficient of regression.

Table 3 Coefficients of regression model.
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3.1 Distribution of green spaces and population density for assessment of environmental justice

The distribution pattern of GS as shown in Fig. 2 helps to examine the relationship between population density and the availability of green spaces in the town. There is a real example of environmental injustice that can be seen in Fig. 2, according to which there is the unequal spatial distribution of parks in areas with high population density. Some of the areas with large portion, the local population lack the availability of single green space or park. The administration has failed to maintain the balance between population growth, its distribution, and GS availability, higher rate of urban built-up, and constant loss of green areas, pushing the area towards environmental threats.

Figure 2 shows the population of Shahdara Town is expanding very fast due to migration and fast growth rate. Green spaces are insufficient in all colonies of the town. According to the census 1998, the population was “35,516 inhabitants” in a square kilometer which has increased to “54,530 persons” per square kilometer in 2017 [36]. Likewise, Table 4 below indicates the density of the population in all colonies of the town indicating the environmental injustice between green areas and population density.

Table 4 Population density and per person green space area.
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Most colonies of this town are deprived of green spaces or playgrounds. According to United Nations (UN), in terms of health standards, the minimum standard for per capita health is 9 square meters [37].

Additionally, Fig. 3 shows the Normalize Difference Vegetation Index (NDVI) values ranging from (− 1 to + 1) of the area under examination. Visually, it can be seen that the area has more built-up infrastructure as compared to natural land. Traffic rate, local industries, and marketing area is going on expansion gradually, which indirectly increase air pollution, land pollution, urban waste, poor air quality in the area, and other environmental issues like solid waste and its management. All of these problems create an imbalance local environment which has negative impacts on human health. Less the green infrastructure more the mental pressure, lessen the trees more the poor quality of air. All of these issues create different challenges for the urban population.

Fig. 3
figure 3

Source: Author (2023)

Normalize difference vegetation index (NDVI).

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Further, the results in Fig. 2 also indicate another issue that is related to social injustice, some portions of the area do not have a single green infrastructure or park, while they have a major population while some areas have less population but there are 2 or more than two green spaces or parks in the same block. This will lead to creating the issues for quality of urban life and threatens the potential of green spaces in urban areas.

4 Discussion

Green spaces, lawns in a house, and parks within the area provides a natural environment to the living species and urban residents. The convenience of playgrounds and parks increases the land value of an area along with natural beauty. The presence of green areas also attracts tourist, and strengthen the area economically by increasing land values [38]. A variety of green areas, gardens, and public parks are additionally a reason for urban quality in the developed world. Although more green areas are available in rural regions, however, they are cultivating fields, not formal green spaces or parks with a planned morphology. As a social platform green spaces are not solely used for natural amenities, they are also used for social activities like weddings, flower exhibitions, and religious purposes [39]. The importance of intrinsic qualities of green areas and parks in contributing to those pleasurable experiences is obvious, so it is desire to touch, smell, observed, and hear the parts of nature [40].

The environmental conditions of urban areas are getting very alarming due to air, water, and land pollution generated by urban people around the world [41]. In a densely populated area, every portion of the urban landscape gets affected due to unplanned infrastructure in form of urban built-up. The government in developing nations is unable to develop new playgrounds and parks in towns with congested population network [42]. Furthermore, it is concluded that due to a lack of urban planning, and population pressure, human activities are going on increasing day by day, which also put pressure on natural habitats and natural resources putting the ecosystem in danger. The cemented infrastructure due to housing construction also increases the Land Surface Temperature which also causes the loss of green spaces in the areas and also causes loss of biodiversity, habitat change, and species extinctions [43]. Therefore, there is a dire need exist to formulate policies related to land allocation plans for housing societies in megacities to shape the cities as more sustainable and resilient.

5 Conclusions

Urban green spaces are not only important ecologically, but they are also significant socially as well as economically having positive mental health impacts as they are the source of interaction between the visitors, and if they are well-developed then they are attractive places for the tourist. The experimental outcomes show that native people use green spaces for various social events and gathering. Green areas improved the life quality of urban habitats which reflects a better picture of the ecological conditions of an area. Our study provides an overview how the increasing rate of population due to migration and birth rate effect the availability of urban green spaces in mega cities. The fast-growing population eventually has adverse impacts on the local environment directly and indirectly affecting people and the natural environment as well in short and long periods. Consequently, research findings show that the presence of green spaces in housing networks plays a very vital role in balancing local environmental quality and positive impacts on the lives of people.

The study concluded that in the city of Lahore where the rate of urbanization is very high, to achieve urban sustainable development goals, there is a need to develop and built more parks and green areas in urban fringes. As the human settlement is on expansion rapidly in this area like the mage cities of the globe, which cause an expansion in built-up infrastructure and indirectly increase the Land Surface Temperature (LST). More built-up areas due to urban expansion, higher the temperature of urban area directly lasses the green spaces and biodiversity. The identification of already existing green spaces in the city and their conditions can help in determining the location of new green spaces that should be easily accessible to all citizens as every citizen has an equal right to enjoy the beauty of nature. Therefore, such development plans should be part of city planning or city master planning to achieve UN goals.