• Coronavirus lockdowns have caused dramatic falls in air pollution in big cities.
  • With factories closed and cars off the road, nitrogen dioxide (NO2) concentration has significantly dropped.
  • But as restrictions were eased in Wuhan, China in early April, pollution levels shot back up to 2019 levels.
air quality pollution environment emissions lockdown Coronavirus china virus health healthcare who world health organization disease deaths pandemic epidemic worries concerns Health virus contagious contagion viruses diseases disease lab laboratory doctor health dr nurse medical medicine drugs vaccines vaccinations inoculations technology testing test medicinal biotechnology biotech biology chemistry physics microscope research influenza flu cold common cold bug risk symptomes respiratory china iran italy europe asia america south america north washing hands wash hands coughs sneezes spread spreading precaution precautions health warning covid 19 cov SARS 2019ncov wuhan sarscow wuhanpneumonia  pneumonia outbreak patients unhealthy fatality mortality elderly old elder age serious death deathly deadly
Lockdowns have improved air quality in cities around the world.
Image: Statista

The air in the world’s biggest cities has become more breathable as coronavirus lockdowns have halted traffic and closed factories. But new data shows that as restrictions are gradually lifted, pollution levels are likely to rise again.

Nitrogen dioxide (NO2) is a pollutant emitted by vehicles and factories, so levels fell when activity slowed. The most dramatic effect has been seen in New Delhi, where traffic usually generates a persistent smog. For the first time in decades, residents have been enjoying clear skies.

But as statistics from Wuhan, China show, once activity resumes, pollution starts to rise again. As restrictions were lifted in the city in early April, air quality began to plummet and pollution returned to 2019 levels.