India's air quality improves as COVID lockdown continues

Widespread measures taken to stop the spread of the COVID-19 pandemic have substantially reduced air pollution in Europe, China, and the United States. According to a report from the European Space Agency, new satellite images have revealed dramatic air quality improvements over India as well.

Cities across India have seen air pollution levels fall by as much as 50 percent following the enforcement of strict COVID-19 quarantine measures. On March 25, the Indian government shut down businesses and restricted the activity of more than 1.3 billion people. 

Maps produced with data from the Copernicus Sentinel-5P satellite show that from March 25 to April 20, there is a remarkable drop in nitrogen dioxide (NO2) concentrations over major urban areas. Compared to the same time last year, Mumbai and Delhi were found to have 40 to 50 percent less NO2 pollution. 

“Thanks to the Tropomi instrument on the Copernicus Sentinel-5P satellite, we are able to observe such high reductions in concentrations in Europe, China, and now India because of the national quarantine measures put in place,” said Sentinel-5P Mission Manager Claus Zehner.

“What is interesting in these new maps are the high values of nitrogen dioxide concentrations over northeast India. Our analysis shows that these clusters are directly linked with the locations of the ongoing coal-based power plants. The largest power station in India, the Vindhyachal Super Thermal Power Station, shows a reduction of only around 15% compared to the same time last year.”

Nitrogen oxide pollution is associated with severe respiratory problems, such as inflammation of the airways, asthma attacks, and reduced lung function. According to the World Health Organization (WHO), about seven million premature deaths are caused by air pollution every year.

Data from the World Air Quality Report shows that Indian cities make up six of the ten most-polluted urban areas on the planet, and New Delhi has the worst air quality anywhere in the world.  

Atmospheric levels of nitrogen dioxide are primarily influenced by vehicle exhaust and power generation, but NO2 concentrations also experience daily fluctuations due to weather conditions. 

“Weather variability is an important factor to consider when making assessments such as these, which is why our team has averaged the data over a longer period of time. In this case, we can clearly see the decreased concentrations are due to human activity,” explained Claus.

India has reported more than 23,000 confirmed COVID-19 cases and nearly 700 deaths. India’s nationwide quarantine was initially planned to last 21 days, but Prime Minister Narendra Modi recently announced that the restrictions will be extended until May 3.

Despite the major benefits for air quality, the lockdown is taking a severe toll on India’s poor and low income communities. 

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By Chrissy Sexton, Earth.com Staff Writer