1. Delhi, India - 153 µg/m3 of PM 2.5
2. Patna, India - 149 µg/m3 of PM 2.51
3. Gwalior, India - 144 µg/m3 of PM 2.52.
4. Raipur, India - 134 µg/m3 of PM 2.53.
5. Karachi, Pakistan - 117 µg/m3 of PM 2.54.
6. Peshawar, Pakistan - 111 µg/m3 of PM 2.5
7. Rawalpindi, Pakistan - 107 µg/m3 of PM 2.56.
8. Khorramabad, Iran - 102 µg/m3 of PM 2.57.
9. Ahmedabad, India - 100 µg/m3 of PM 2.58.
10. Lucknow, India - 96 µg/m3 of PM 2.5
Air pollution already kills 3.3 million people a year, and that number could double by 2050.The most harmful pollutant to human health is called PM 2.5, short for particle matter that's less than 2.5 microns in diameter. It's found in soot, smoke, and dust and lodges in the lungs causing long-term health problems like asthma and chronic lung disease. PM 2.5 starts to become a health problem when there is more than 35.5 micrograms of PM 2.5 per cubic meter (written like 35.5 µg/m3) of air, according to the Environmental Protection Agency. But the World Health Organizations recommends that PM 2.5 SHOULDN'T exceed 10 µg/m3. The most polluted cities on Earth have anywhere from 9 to 15 times that amount – based on information from the WHO. Check them out: