5 Most Polluted Cities in the World

2. Ghaziabad, India

Annual average PM2.5 concentration (μg/m³): 102

The second most polluted city in the world is also the second most polluted city in India. Ghaziabad, located in Utter Pradesh, still has something to cheer about as its PM2.5 concentration is decreasing year on year, albeit perhaps not fast enough.