North India’s air is cleaner than it’s ever been in over 20 years — and here are the pictures that prove it
Apr 24, 2020, 10:28 IST
The anomaly — air pollution in North India is at a 20-year low
NASA
Maps from NASA show how the aerosol optical depth (AOD) measurements over India from 2016 to 2020 between March 31 to April 5. The last map in the series, dubbed ‘anomaly’, shows how the AOD in 2020 compares to the average between 2016 to 2019.
The data was retrieved by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite.
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The pollution drop can be seen on a chart
NASA
In the first few days of the lockdown, there was a drop in aerosol levels, however, it was difficult to determine whether the change was a direct result of people staying at home or just better weather.
“After the rainfall, I was really impressed that aerosol levels didn’t go up and return to normal. We saw a gradual decrease, and things have been staying at the level we might expect without anthropogenic emissions,” said Gupta.
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Horizons re-appear after decades
GauravBhanu99/Twitter
In congruence, ground observation stations in India also reported a decrease in particle pollution in the region. Some people in the northern state of Punjab even reported seeing the Himalayas for the first time in decades.
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Southern India is has a long way to go
BCCL
Traffic jam in Bengaluru during the lockdown
North India may have gotten rid of its pollution, but the same cannot be said for its southern states. Satellite data show aerosol levels have not yet decreased to the same extent. According to Gupta, levels seem to be slightly higher than in the past four years. The reasons are unclear but they could be related to recent weather patterns, agricultural fires, winds, or other factors.
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The fairy tale may come to an end
BCCL
The air may be clear right now, but scientists expect the aerosol levels to rise again in the coming weeks. Dust concentration is normally lower in March and early April before the summer temperatures kick in. It’s likely that strong westerly winds will blow sand in from the Thar Desert and Arabian Peninsula. It’s going to be a game of waiting and watching to see if the overall AOD will remain below normal.
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