Abstract
The COVID-19 pandemic has affected severely the economic structure and health care system, among others, of India and the rest of the world. The magnitude of its aftermath is exceptionally devastating in India, with the first case reported in January 2020, and the number has risen to ~31.3 million as of July 23, 2021. India imposed a complete lockdown on March 25, 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 the north-to-south stretch of the country. In general, all assessed air pollutants showed a substantial decrease in AQI values during the lockdown compared with 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 for PM2.5, PM10, and CO, and maximum reduction of 40–60% of NO2 has been observed herein, while the data was average for northern, western, and southern India. SO2 and O3 showed an increase over a few cities as well as a 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 the 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 the 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%.
Highlights
A novel infectious disease for the first time was identified in Wuhan, China, in late December 2019 and was named as 2019 novel corona virus and later on renamed as the COVID-19 (Chen et al, 2020) on February 11, 2020 by the International Committee on Taxonomy of Viruses
Meteorologically normalized AQI data of each pollutant has been used to see the relative changes in AQI during the lockdown period compared with the reference period across the 16 Indian cities
We have witnessed a significant increase in O3 over Kolkata (∼18%, from 14.5 ± 4.5 to 17.5 ± 11.6; two-tailed t-value: 2.4) and Visakhapatnam (∼20%, from 6.1 ± 2.2 to 7.6 ± 4.2; two-tailed t-value: 2.9) during the lockdown period compared with the reference period
Summary
A novel infectious disease for the first time was identified in Wuhan, China, in late December 2019 and was named as 2019 novel corona virus and later on renamed as the COVID-19 (Chen et al, 2020) on February 11, 2020 by the International Committee on Taxonomy of Viruses. Later on in January 2020, the World Health Organization (WHO) revealed human transmission of COVID-19. Air Quality During COVID-19 Lockdown through respiratory droplets (WHO, 2020), which subsequently got spread throughout the China, and the outbreak was turned into an epidemic (Dutheil et al, 2020). On January 30, 2020, the WHO declared the COVID-19 as a global pandemic. To slow down the rate of spread of virus, almost all the countries have followed partial-to-complete lockdown practice (Tosepu et al, 2020). The industrial activities were shut down globally due to the imposed lockdown. The informal economic sector suffered a major fall along with the transport sector as most of the countries imposed complete lockdown. Global fossil fuel demand dropped down severely, as industrial and transport sectors came to a halt for a while across the world.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
