Special Issue on COVID-19 Aerosol Drivers, Impacts and Mitigation (IV)

Abirlal Metya This email address is being protected from spambots. You need JavaScript enabled to view it.1,2, Panini Dagupta1,3, Santanu Halder1,2, S. Chakraborty1,2, Yogesh K. Tiwari1,2

1 Center for Climate Change Research, Indian Institute of Tropical Meteorology, MoES, Pune, India
2 Department of Atmospheric and Space Sciences, Savitribai Phule Pune University, Pune, India
3 Department of Meteorology and Oceanography, College of Science and Technology, Andhra University, Visakhapatnam, Andhra Pradesh, India


Received: May 17, 2020
Revised: July 12, 2020
Accepted: July 12, 2020

 Copyright The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.

Download Citation: ||https://doi.org/10.4209/aaqr.2020.05.0240 

Cite this article:

Metya, A., Dagupta, P., Halder, S., Chakraborty, S. and Tiwari, Y.K. (2020). COVID-19 Lockdowns Improve Air Quality in the South-East Asian Regions, as Seen by the Remote Sensing Satellites. Aerosol Air Qual. Res. 20: 1772–1782. https://doi.org/10.4209/aaqr.2020.05.0240


  • Air quality improved India and China during the COVID-19 outbreak is investigated.
  • Satellite data (OMI and AIRS) for CO, NO2 and SO2 is used.
  • NO2 was reduced the most; CO to some extent and SO2 experienced a nominal reduction.


The appearance of COVID-19 in December, 2019 in China and its rapid spread all over the globe, forced the governments to severely curb the social and economic activities of their respective countries. Barring the essential services, most of the business activities and transport sectors have been suspended and an unprecedented lockdown imposed over major economies in the world. South-East Asian regions, such as India and China, were no different. As a result, the pollutant level has gone down over these regions, and the air quality improved somewhat better than it was before the lockdown. This study uses satellite retrievals and attempts to estimate the extent of the reduction of major pollutants, like carbon monoxide (CO), nitrogen dioxide (NO2) and sulfur dioxide (SO2) in India and China during January to April, 2020. We have calculated anomalies of pollutants during the lockdown period relative to their long-term records. NO2, which has significant emissions from the transport sector, is reduced on an average by 17% over India and 25% over China. SO2, which mainly emits from power plants, shows significant reductions (approx. 17%) especially over the Eastern sector of India. CO is found to be reduced by 6.5% over north-central China. The differential reduction was attributed to man made versus natural activities. This study is helpful to policy makers in mitigating the air-pollution on a long-term perspective.

Keywords: SARS-CoV-2; Coronavirus; COVID-19; Air quality; CO; NO2; SO2.

Aerosol Air Qual. Res. 20:1772-1782. https://doi.org/10.4209/aaqr.2020.05.0240 

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