These maps are created by NASA and the European Space Agency using Sentinel 5P images to visualize the impact of lockdown due to Coronavirus across China. The map on the left is before the quarantine and on the right is during the quarantine. The Sentinel 5P satellites have detected significant decreases in nitrogen dioxide (NO2) over China. By January 23, 2020, Chinese authorities had shut down transportation going into and out of Wuhan, as well as local businesses, in order to reduce the spread of the disease. The maps here show the concentrations of nitrogen dioxide, a noxious gas emitted by motor vehicles, power plants, and industrial facilities. Scientists argue that this might also be the impact of the Lunar New Year celebration, but the reduction rate in these materials have exceeded any measures seen in the past.