| Summary: | In 2020, COVID-19 was proclaimed a pandemic by the World Health Organization, prompting several nations throughout the world to block their borders and impose a countrywide lockdown, halting all major manmade activities and thus leaving a beneficial impact on the natural environment. We investigated the influence of a sudden cessation of human activity on tropospheric NO<sub>2</sub> concentrations to understand the resulting changes in emissions, particularly from the power-generating sector, before (2010–2019) and during the pandemic (2020). NO<sub>2</sub> was chosen because of its short lifespan in the Earth’s atmosphere. Using daily tropospheric NO<sub>2</sub> column concentrations from the Ozone Monitoring Instrument, the geographic and temporal characteristics of tropospheric NO<sub>2</sub> column were investigated across 12 regions in India, Pakistan, China, and South Korea (2010–2020). We analyzed weekly, monthly, and annual trends and found that the NO<sub>2</sub> concentrations were decreased in 2020 (COVID-19 period) in the locations investigated. Reduced anthropogenic activities, including changes in energy production and a reduction in fossil fuel consumption before and during the COVID-19 pandemic, as well as reduced traffic and industrial activity in 2020, can explain the lower tropospheric NO<sub>2</sub> concentrations. The findings of this study provide a better understanding of the process of tropospheric NO<sub>2</sub> emissions over four nations before and after the coronavirus pandemic for improving air quality modeling and management approaches.
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