Coronavirus outbreak: Study reveals lockdown-like situations better air quality in India

New Delhi, June 04: A series of lockdowns that were enforced due to the outbreak of COVID-19 has led to a large improvement in air quality in India, say scientists. These scientists suggest that such interventions may be used as a possible emergency measure to combat severe air pollution episodes like those witnessed in Delhi-NCR region during the winter months.

Ahead of the World Environment Day that is celebrated on June 5, experts have outlined several environmental factors that saw improvements in India as a result of the lockdowns, namely air quality, noise pollution, water quality, and biodiversity among others due to reduced industrial and human activities.

On March 24, Prime Minister Narendra Modi called for a nationwide lockdown for 21 days, limiting the movement of people in India as a preventive measure against the COVID-19 pandemic. Since then, the lockdown has been extended many times with gradual lifting of restrictions.

"There is a large improvement in air quality, especially in urban areas -- from alarming or poor to satisfactory or good. The main reason is reduced human activities," said S K Satheesh, Professor at Centre for Atmospheric and Oceanic Sciences, Indian Institute of Science (IISc) Bangalore.

"On an average, reduction in particulate matter (PM) concentrations over southern part of India is around 50 to 60 per cent, and over the Indo-Gangetic basin, including Delhi, UP, Bihar, West Bengal etc it is as much as 75 per cent," he further said.

According to two studies, published in the journal Geophysical Research Letters in May, the levels of two major air pollutants, including nitrogen dioxide, drastically reduced since lockdowns were enforced worldwide in response to the COVID-19 pandemic.

"In India, satellite data has shown a significant drop in particulate matter or aerosol levels after the COVID-19 lockdown over most parts of the country," Satheesh said.

"Our field measurements show that there is a substantial reduction in the concentration of suspended particulate matter (PM), a major component of air pollution, in the atmosphere due to reduced human activities as a consequence of the lockdown," he said.

The scientist further explained that multi-spectral measurements of aerosol absorption, in addition to data available from Central Pollution Control Board (CPCB), indicate that the drastic decrease in pollution levels is mainly due to a reduction in fossil fuel burning emissions.