Satellite data show that aerosol levels have dropped significantly since the COVID-19 lockdown began.
On March 25, 2020, the Indian government placed its 1.3 billion citizens under a strict lockdown to reduce the spread of the COVID-19 coronavirus. The country-wide mandate decreased activity at factories and severely reduced car, bus, truck, and airplane traffic. After just a week of reduced human activities, NASA satellite sensors observed aerosol levels at a 20-year low for this time of year in northern India.
Every year, aerosols from anthropogenic (human-made) sources contribute to unhealthy levels of air pollution in many Indian cities. Aerosols are tiny solid and liquid particles suspended in the air that reduce visibility and can damage the human lungs and heart. Some aerosols have natural sources, such as dust storms, volcanic eruptions, and forest fires. Others come from human activities, such as the burning of fossil fuels and croplands. Human-made aerosols tend to contribute most of the smaller particles that have greater potential for damaging human health.
“We knew we would see changes in atmospheric composition in many places during the lockdown,” said Pawan Gupta, a Universities Space Research Association (USRA) scientist at NASA’s Marshall Space Flight Center. “But I have never seen aerosol values so low in the Indo-Gangetic Plain at this time of year.”
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