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

Sunil Gulia This email address is being protected from spambots. You need JavaScript enabled to view it.1, Nitin Goyal2, Saurabh Mendiratta1, Tridipa Biswas1, S.K. Goyal1, Rakesh Kumar3 

1 CSIR-National Environmental Engineering Research Institute, Delhi Zonal Centre, Naraina, New Delhi -110028, India
2 CSIR-National Environmental Engineering Research Institute, Mumbai Zonal Centre, Worli, Mumbai – 400018, India
3 CSIR-National Environmental Engineering Research Institute, Nehru Marg, Nagpur, 440020gpur 440020, India

Received: June 19, 2020
Revised: January 2, 2021
Accepted: January 2, 2021

 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.200308  

Cite this article:

Gulia, S., Goyal, Nitin, Mendiratta, S., Biswas, T., Goyal, S.K., Kumar, R. (2021). COVID 19 Lockdown - Air Quality Reflections in Indian Cities. Aerosol Air Qual. Res. 21, 200308. https://doi.org/10.4209/aaqr.200308


  • Air quality impact assessment in 46 Indian cities during lockdown due to COVID-19.
  • Impact of lockdown on air quality was not homogeneous throughout India.
  • Impact of lockdown was more severe in large cities compared to smaller ones.
  • Impact of lockdown was more significant in Northern India compared to other parts of India.
  • Background concentrations of PM2.5 and NOx are higher in Northern Indian cities.


The emergence of COVID-19 put pressure on the Governments of most of the countries in the world to enforce nationwide lockdown (restriction of all non-essential activities) to curtail the spread of infection. The nationwide lockdown created an adverse impact on the economies around the world and altered the day-to-day life of people. The restrictions on pollution generating activities during the lockdown period resulted in an overall improvement of the air quality throughout the world including India. This study evaluated the impact on air quality in 46 cities throughout India and the findings indicate that on average, PM2.5 and NOx, concentrations reduced by about 34% and 60%, respectively at different locations in India. PM2.5 concentrations reduced by about 23%, 16%, 32%, and 28% in small, medium, large and megacities, respectively. However, the reduction in NOx concentrations was dissimilar to PM2.5 in these cities. The findings further suggested that the impact of lockdown on air quality was not homogenous across the country and was probably due to varying background contributions. The average concentrations of PM2.5 and NOx at background stations were found higher in large and mega cities than the smaller cities. The PM2.5 concentrations at background stations were higher in North India in comparison to other parts of India.

Keywords: Restricted emission activities, Populated cities, Background concentrations, India, Lockdown

Don't forget to share this article 


Subscribe to our Newsletter 

Aerosol and Air Quality Research has published over 2,000 peer-reviewed articles. Enter your email address to receive latest updates and research articles to your inbox every second week.