Himalaya air quality impacts from the COVID-19 lockdown across the
Indo-Gangetic Plain
Abstract
Starting in January 2020, the novel coronavirus, now known as acute
respiratory syndrome coronavirus (SARS-CoV-2) and the disease that it
causes (COVID-19) has had significant impacts on human health, the
environment and the economy globally. The rapid lockdown that occurred
as well as its well documented timing in various locations allows for an
unprecedented opportunity to examine the impact of air pollution from
densely populated regions has on adjacent and pristine environments.
Here we use in-situ and satellite observations to show that there was a
step function decrease in two key indicators of air quality, nitrogen
dioxide and airborne particulates, in locations within the Indo-Gangetic
Plan (IGP) as a result of the Spring 2020 lockdown. Based on anomaly
patterns, we find a dipole response with a statistically significant
reduction in air pollution along the western IGP and Himalaya and an
increase in air pollution in the eastern IGP and Himalaya. We show that
spatial variability in the reductions in economic activity across
northern India and the adjoining countries of Nepal, Pakistan and
Bangladesh contributed to this dipole as did a persistent atmospheric
circulation anomaly across the region during the lockdown.