Astounding images taken by pollution monitoring satellites show a significant decrease in toxic gases above China over the last several weeks, likely in part due to an economic slowdown caused by the new coronavirus outbreak, NASA said.

Images released by the space agency show yellowish nitrogen dioxide cloaking a wide area of land north and east of Wuhan, where the virus originated, during the first few weeks of January. By mid-February, the cloud was almost entirely gone.

These effects would correlate with Chinese authorities ordering a city-wide quarantine of Wuhan at the end of January and the halting of transportation into and out of that city and several others to prevent the spread of coronavirus. Nitrogen dioxide, which is harmful to human health and the environment, is emitted by motor vehicles, power plants and industrial facilities.