NO2 (nitrogen dioxide) in the tropospheric column (mol cm−2) for the first 14 days of spring 2019 (top) and 2020 (bottom), respectively, several weeks after many countries worldwide initiated lockdowns [maps generated with the Giovanni online tool (Prados et al. 2010) using data from the Ozone Monitoring Instrument on NASA’s Aura satellite, 30% cloud screened, daily 0.25° resolution]