This map shows you nitrogen dioxide emissions hot spots around the globe, with the highest levels of NO2 displayed as white patches.

The culprit: Nitrogen dioxide emissions come from fossil fuels being burned. Combustion engines in cars, buses, and trains all emit NO2, as do factories, power plants, and forest fires. It causes lung and respiratory problems—and it shorten life spans.

The highest concentrations: In this composite, they’re mostly in big cities like Moscow, Beijing, Lima, Jakarta, and Mexico City, geographer Tim Wallace explains. But less well-populated places have high concentrations too, like Korba in India, which has a population of 360,000 yet exceptionally high nitrogen dioxide emissions thanks to its industrial sector. There are also hot spots in south central Africa caused by biomass fires.

How was this graphic made? The data was collected during August and September 2018. It’s a composite of images taken by from the European Space Agency’s Sentinel-5P, an Earth observation satellite. The graphic was pulled together by a data analysis startup called Descartes Labs.

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