The isolation measures by Covid 19 change our environment. The images of the Copernicus Sentinel-5 satellite of the ESA to show. The images show the emission of Nitrogen oxides over Europe in the period between January and March 2020. Especially in Northern Italy, a marked decrease is seen. In China, the data of the ESA satellite show a similar drastic decrease of nitrogen. On the images of the period is
to see from mid-December to March. The Nasa researchers-Fei Liu of the “Science Times says” a decline was also observed during the recession of 2018..
Such a drastic change you have observed but never.
Sources: ESA and the Science Times