AUTHOR=Mishra Amit Kumar , Rajput Prashant , Singh Amit , Singh Chander Kumar , Mall Rajesh Kumar 

TITLE=Effect of Lockdown Amid COVID-19 on Ambient Air Quality in 16 Indian Cities

JOURNAL=Frontiers in Sustainable Cities

VOLUME=Volume 3 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/sustainable-cities/articles/10.3389/frsc.2021.705051

DOI=10.3389/frsc.2021.705051

ISSN=2624-9634

ABSTRACT=COVID-19 pandemic has affected severely the India’s and rest of the world’s economic structure and health care system, among others. The magnitude of its aftermath is exceptionally devastating in India, with 1st case reported in January, 2020 and number has risen to ~31.3 million as on 23rd July, 2021. India imposed the complete lockdown on 25th of March which severely impacted migrant population, industrial sector, tourism industry and overall economic growth. Herein, the impacts of lockdown and unlock phases on ambient atmospheric air quality variables have been assessed across 16 major cities of India covering north-to-south stretch of the country. In general, all assessed air pollutants showed a substantial decrease in AQI values during the lockdown as compared to the reference period (2017‒2019) for almost all the reported cities across India. On an average, about 30‒50% reduction in AQI has been observed of PM2.5, PM10, and CO, and maximum reduction of 40‒60% of NO2 has been observed herein while the data was averaged for northern, western, and southern India. The SO2 and O3 showed increase over few cities as well as decrease over the other cities. Maximum reduction (49%) in PM2.5 was observed over north India during the lockdown period. Furthermore, the changes in pollution levels showed a significant reduction in first three phases of lockdown and a steady increase during subsequent phase of lockdown and unlock period. Our results show the substantial effect of lockdown on reduction in atmospheric loading of key anthropogenic pollutants due to less-to-no impact from industrial activities and vehicular emissions, and relatively clean transport of air-masses from upwind region. These results indicate that by adopting cleaner fuel technology and avoiding poor combustion activities across the urban agglomerations in India could bring down ambient levels of air pollution at least by 30%.