Fig. 3From: COVID-19 lockdown and natural resources: a global assessment on the challenges, opportunities, and the way forwardNitrogen dioxide (NO2) levels in the troposphere before and after anthropause period. For example, the NO2 content in Madrid, Milan and Rome decreased by about 45%, and by 54% in Paris, compared to 2019. From Copernicus Sentinel data 2019–2020 processed by KNMI/ESA (Sources: ESA 2020; NASA 2020)Back to article page