Coronavirus slowdown: Nasa images show ‘dramatic’ drop in China’s air pollution

Satellite images taken by US space agency Nasa have shown a dramatic decline in levels of air pollution over China, which is "partly" an outcome of the economic slowdown prompted by the coronavirus outbreak in the country, it said.

The Nasa maps showed that levels of nitrogen dioxide -- a noxious gas emitted by motor vehicles and industrial facilities -- are falling this year following a record decline in industrial activities in China as manufacturers stop work in a bid to contain coronavirus, reports BBC.

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The reduction in nitrogen dioxide levels was first apparent in Wuhan city -- the epicentre of the virus outbreak -- but then spread across China, scientists at Nasa said.

Nasa compared the images from the first two months of 2020 with the same period last year.

The decline in China's air pollution levels coincided with restrictions imposed on transportation and business activities, as millions of people are being quarantined, the space agency noted.

NASA and the European Space Agency (ESA) have used pollution monitoring satellites to analyse the changes, reports Yahoo News.

They then released two maps to show the differences.

Nasa compared the images from the first two months of 2020 with the same period last year. Image taken from Nasa/ European Space Agency (ESA)

"This is the first time I have seen such a dramatic drop-off over such a wide area for a specific event," Fei Liu, an air quality researcher at Nasa's Goddard Space Flight Centre, said in a statement, according to the BBC report.

A decline in nitrogen dioxide levels was observed during the economic recession in 2008, but that decrease was more gradual, she added.

Chinese Lunar New Year celebrations in late January and early February have previously been linked to decreases in pollution levels, but the levels normally went up again once the celebrations were over, Nasa noted.

"This year, the reduction rate is more significant than in past years and it has lasted longer," Liu told BBC.

"I am not surprised because many cities nationwide have taken measures to minimise the spread of the virus," she added.

China has so far recorded nearly 80,000 confirmed coronavirus cases since the outbreak began late last year.

The virus has spread to more than 50 countries, but the vast majority of infections and deaths are in China.