These 10 cities have the worst air pollution in the world, and it is up to 15 times dirtier than what is considered healthy

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 Organisations recommends that PM 2.5 shouldn’t even 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 — and you might be surprised which make the top 10 list. Check them out:

10. Lucknow, India – 96 µg/m3 of PM 2.5

Lucknow, a city in northern India, starts off the top 10 cities with the worst air pollution levels list. It still significantly has a high average air pollution level that falls into the “unhealthy” category. Vehicle emissions are a major factor in Lucknow’s air pollution problem.

9. Ahmedabad, India – 100 µg/m3 of PM 2.5

India’s western city Ahmedabad gets its air pollution in part from the major construction happening in the city.

8. Khorramabad, Iran – 102 µg/m3 of PM 2.5

Khorramabad, a city in western Iran, had the country’s highest air pollution levels. One of the most populous cities in Iran, Khorramabad is an agriculture hub, which likely contributes to its air pollution problems.

7. Rawalpindi, Pakistan – 107 µg/m3 of PM 2.5

Rawalpindi, the twin city of Pakistan’s capital Islamabad, has a high average air pollution because of its heavy use of private vehicles. Rawalpindi just launched a mass transportation system in 2015, so maybe that will knock it off the top 10 list in the not-too-distant future.

6. Peshawar, Pakistan – 111 µg/m3 of PM 2.5

With a population of 3.5 million people, Peshawar joins the list because of the usual suspects (vehicle and industrial emissions), as well as brick kiln emissions from the brick-making industry in the city.

5. Karachi, Pakistan – 117 µg/m3 of PM 2.5

Vehicle and industrial emissions combined with rapid urbanization puts Karachi as the city in Pakistan with the most air pollution.

4. Raipur, India – 134 µg/m3 of PM 2.5

Fans reach out to Bollywood actor Amitabh Bachchan in Raipur.
Raipur, a city in central India, is the fourth most polluted Indian city in terms of average PM 2.5 levels. The reason for the high pollution is coal-powered plants and aluminum and steel production.

3. Gwalior, India – 144 µg/m3 of PM 2.5

Of the top 20 most polluted cities, 13 were in India — including Gwalior. The Times of India attributes Gwalior’s bad air pollution to coal-powered plants, cars, and inefficient energy use in buildings.

2. Patna, India – 149 µg/m3 of PM 2.5

Patna, the second largest city in eastern India, is a major agricultural trade center, suffers from high pollution in part because of transportation, power generation and other industries. Its PM 2.5 levels are considered “unhealthy.”

1. Delhi, India – 153 µg/m3 of PM 2.5

Delhi, is the only one on the WHO’s list that qualifies as a “very unhealthy” average PM 2.5 level. Its high pollution level is due to motor vehicles and nearby factories.

In comparison, Beijing’s average PM 2.5 is 56, though other calculations put it much higher.

And New York’s average PM 2.5 level is a relatively healthy 14.

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