Pollution level in North India lowest in 20 years due to lockdown: NASA
In the aftermath of nationwide lockdown in the country, air pollution over Northern India has reduced to a 20-year-low at this time of the year, as per the National Aeronautics and Space Administration (NASA).
According to a report published by the US space agency, its satellite sensors observed aerosol levels at a 20-year-low after just a week of reduced human activities in Northern India. The data shows aerosol optical depth (AOD) from January 1 to April 5, 2020, as compared to the 2016-2019 average, which retrieved by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite.
Notably, aerosols from human activities contribute to unhealthy levels of air pollution around many cities in the country, majoritarily in the Ganges Valley of northern India during the early spring season. They are tiny solid and liquid particles present in the air that reduce visibility and can pose danger to the human heart and lungs.
In urban areas, coal-fired power plants, movement of transports, factories, and other industrial operations produce nitrates and sulphates, whereas in rural areas, organic carbon from cooking, heating stoves and crop burning, and smoke rich in black carbon – all together contributed to severe air pollution. With the imposition of lockdown to stem the transmission of Coronavirus, human-made emissions have reduced significantly making the air cleaner and fresher to breathe.
Talking about the development, Pawan Gupta, a USRA scientist at NASA, said that he has never seen aerosol values low in the Indo-Gangetic Plains at this time of the year. According to the scientist, it was initially difficult to observe a significant change in the pollution level. However, after heavy rainfall around March 27, the aerosols concentration cleared over the skies of northern India. In the report, NASA’s Pawan Gupta added that aerosol levels did not go up even after the rain (which usually rises after heavy precipitation). Also, there was a gradual decrease in the aerosol level and it has remained subtle since the findings.
“This a model scientific experiment,” said Robert Levy, program leader for NASA’s MODIS aerosol products talking about the lockdown and its impact on the pollution level. However, the scientists are expecting the aerosol levels to increase moderately in parts of the country as the dust storms begin in the upcoming weeks.
In Southern India on the other hand, the satellite data show that aerosol levels have not decreased to the same extent. Interestingly, the levels appear to be slightly higher than in the last four years. While the reasons are still unclear to the scientists, they believe it could be due to varied reasons including changing weather patterns, winds, or other factors.
Earlier in April, residents of Punjab’s Jalandhar city were able to see the snow-covered mountains of the Himalaya’s Dhauladhar range, which is approximately 200 km away from the state – all thanks to the decrease in air pollution to the COVID-19 lockdown. They shared visuals of the mountain ranges from their houses which went viral on social media.
India’s 1.3 billion population has been under a strict lockdown since March 25 in a bid to curb the spread of COVID-19 pandemic. The lockdown was extended by the Modi government for 19 days till May 3 after the completion of its 21-day first phase on April 14. Due to the lockdown, movement of citizens and vehicles has been blocked, factories and industries are shut albeit few exceptions. On April 23, India’s Coronavirus positive cases crossed 21,000 and more than 680 people have died from the disease.