It’s been a month since the country has been under a complete lockdown to curb the spread of COVID-19 virus. While this has worked out well to contain the spread of the virus, it has also positively impacted the quality of air in the northern regions of India. Thanks to the fact that virtually all factories and industries have been shut, construction that has come to a grinding halt and significantly reduced vehicular traffic.

A report by US government space agency, National Aeronautics and Space Administration (NASA), suggests that the aerosol levels in North India are at a 20-year low for this time of the year. They have also released satellite images showing the Aerosol Optical Depth (AOD) measurements over India during the period of March 31 to April 5, for each year from 2016 through 2020, which clearly shows the drastic change in the quality of air.

Aerosols are tiny solid and liquid particles suspended in the air that reduce visibility and can damage the human lungs and heart. While there are natural sources of aerosols like dust storms, forest fires, etc., human-made aerosols contribute majorly to the air pollution in various cities and also pose a greater risk to health.

The majority of aerosols are produced by motor vehicles, coal-based powerplants, and other industries that produced nitrates and sulphates. Rural areas add smoke from cooking and farm burning, further increasing the quantity of aerosols. This 2020 lockdown has brought most of these activities to a halt, resulting in cleaner air in the northern regions of India. On the flipside, the data shows that aerosol levels haven’t decreased in South India at a similar pace and are in fact still high. The reason for this is still unknown.