Major cities have come to a standstill amid the coronavirus lockdowns, and while that may be incredibly inconvenient, it’s also having a positive impact on the environment.

An analysis by IQAir, a global air quality information and tech company, shows that during a three-week period of lockdowns, pollution in major cities has decreased by as much as 60 percent when compared to 2019.

Researchers studied 10 major cities around the world with high levels of COVID-19 cases and strict lockdown measures, and looked at levels of harmful microscopic particulate matter (called PM2.5), which is considered a dangerous pollutant. Seven of the 10 cities studied, including New Delhi, Seoul, Wuhan, and Mumbai, saw notable improvements in air quality, and drops in their levels of PM2.5 pollution.

New Delhi, which often ranks as the world’s most polluted city, saw a 60 percent reduction in its PM2.5 levels between March 23 and April 13, from the same period last year. In Seoul, there was a 54 percent drop in PM2.5 levels between February 26 and March 18, and Wuhan — where the virus originated — registered a 44 percent drop in air pollution levels between February 26 and March 18. Los Angeles also enjoyed its longest stretch of clean air on record, with PM2.5 levels down by 51 percent from the previous four-year average.

The decrease in air pollution throughout the world has been very evident. In Northern India, the Himalayas were suddenly visible after the strict lockdown imposed throughout the country, and Germany recently set a solar power record after a drop in air pollution cleared the skies.