Analyzing the Impact of Nationwide Lockdown on Air Pollution Levels in Indian Cities—And What We Can Learn from It

Abstract

Air quality is of utmost importance to human health. Indian cities rank among the most polluted cities in the world, and Delhi tops the list. The effects of air pollution on agriculture, the economy, traffic accidents, and human health are numerous. The coronavirus pandemic brought with itself a nationwide lockdown to prevent the spread of the virus. Nationwide lockdown in India started on 25th March 2020 which brought everything to a standstill—vehicular as well as industrial activities. As a result, major Indian cities saw a significant and sudden improvement in air quality. This research work focuses on analyzing the impact of nationwide lockdown on air quality in major Indian cities—Delhi, Mumbai, Hyderabad, and Chennai. This research aims to understand and make sense of the sudden improvement in air quality during the nationwide lockdown by using data visualization techniques. We have analyzed the levels of individual air contaminant species for a period of 2016–2020 (till 22nd May) focusing mainly on the months in which lockdown happened and comparing them with corresponding data from the previous years. Our analyses show that air pollution in major Indian cities is mostly anthropogenic and that when such activities came to a halt, air quality improved. COVID-19 had a substantial impact on air quality during the nationwide lockdown; however, as our analyses clearly demonstrated the cause of these improvements to be a full shutdown of the economy, such improvements are not sustainable in the long run, and pollution levels will once again rise to pre-COVID levels after these restrictions are lifted. It is imperative to adopt an airshed approach to tackle air pollution in cities like Delhi where surrounding regions also contribute to the city’s pollution.