5 Most Polluted Cities in the World

3. Hotan, China

Annual average PM2.5 concentration (μg/m³): 101.5

Hotan has improved from its 2020 peak as the world’s most polluted city when it had an air quality of PM 2.5 of 110.2 μg/m³; this means that the particles in the air are of a size sufficient to enter one’s bloodstream.