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Satellite images showing the mean tropospheric nitrogen dioxide density changes over China. Photo: NASA

Pollution levels have plummeted over China and it's "partly related to the economic slowdown following the outbreak of coronavirus," NASA said in a statement accompanying the release of satellite images demonstrating the nitrogen dioxide (NO2) changes.

Driving the news: The outbreak caused China's factory activity to fall to a record low of 35.7 in February from 50.0 in January, officials said Saturday, per the Financial Times. NO2, a key contributor to smog and a major health hazard, is the gas that's emitted by motor vehicles, power plants and other industrial facilities.

NO2 levels in Wuhan, China, the epicenter of the outbreak. Photo: NASA
This is the first time I have seen such a dramatic drop-off over such a wide area for a specific event."
— Fei Liu, air quality researcher at NASA’s Goddard Space Flight Center

Zoom in: NASA scientists first noticed the reduction in NO2 pollution in January near Wuhan, the epicenter of the COVID-19 outbreak. They then noticed changes in pollution levels across the country as the virus spread.

The big picture: Fei Liu, an air quality researcher at NASA’s Goddard Space Flight Center, recalled seeing a fall in NO2 levels over several countries during the economic recession that began in 2008, but that was more gradual.

  • Lunar New Year celebrations may have contributed to the big drop, but Liu noted the levels had not rebounded — as happened when there was a dip in Beijing during the 2008 Olympics before they rose again after the Games finished.
  • "This year, the reduction rate is more significant than in past years and it has lasted longer," Liu said. "I am not surprised because many cities nationwide have taken measures to minimize spread of the virus."

Go deeper: Coronavirus hits China's tech manufacturing

Go deeper

Updated 20 mins ago - Sports

Naomi Osaka eliminated from Olympic tennis tournament

Czech 42nd-ranked Marketa Vondrousova (L) shakes hands with Japan's Naomi Osaka after their Tokyo 2020 Olympic Games women's singles third round tennis match at the Ariake Tennis Park in Tokyo on Tuesday. Photo: Giuseppe Cacace/AFP via Getty Images

Naomi Osaka was eliminated from the Olympics after losing her Tokyo tennis tournament match 6-1, 6-4 in the third round to Czech Marketa Vondrousova on Tuesday.

Of note: Japan's Osaka is the women's world No. 2, while is Vondrousova ranked No.42.

Updated 25 mins ago - Sports

Olympics dashboard

🏄‍♀️: American Carissa Moore wins first-ever women's Olympic gold in surfing

🎾: Naomi Osaka eliminated from Olympic tennis tournament

🏊‍♀️: Teen swimmer Lydia Jacoby wins first U.S. women's Tokyo Games gold

✊🏿: Costa Rican gymnast pays tribute to Black Lives Matter in Olympic routine

🤖: The robot Olympics

🌡: Heat wave brings scorching temperatures to Tokyo Olympics

Go deeper: Full Axios coverage - Medal tracker

American Carissa Moore wins first-ever women's Olympic gold in surfing

Carissa Moore of Team USA surfs during the women's Quarter Final on day four of the Tokyo 2020 Olympic Games at Tsurigasaki Surfing Beach in Ichinomiya, Chiba, Japan, on Tuesday. Photo: Ryan Pierse/Getty Images

Team USA's Carissa Moore won gold in the first-ever Olympic women's surfing final, at the Tokyo Games on Tuesday.

Of note: Brazil's Italo Ferreira won the gold medal in the inaugural men's Olympic surfing contest.