These Major Cities Rank Among the Most Polluted in the World, 2 Are in the US

By Sam Stebbins  •  August 3, 2025
smoke billows from the stacks of smoke stackshttps://climate-crisis-247-bucket.nyc3.cdn.digitaloceanspaces.com/wp-content/uploads/2025/08/07210705/svooloyzqpc-150x150.jpg

The United States has some of the cleanest air in the world. Largely due to government regulations enacted in the second half of the 20th century – including the Air Quality Act of 1967 and the Clean Air Acts of 1963 and 1970 – concentrations of harmful pollutants released into the atmosphere during a period of rapid industrial growth have been drastically reduced. Partially as a result, fewer than two dozen countries globally have a lower annual average concentration of harmful pollutants in the air than the United States, according to IQAir, an air quality research organization.

Notably, however, smoke produced by thousands of wildfires burning across millions of acres of Canadian wilderness are drifting south across the U.S. border, reducing air quality and presenting health risks for millions of Americans.

The Air Quality Index, or AQI, is a standardized indicator of the concentration of harmful pollutants suspended in the air, measured on a scale of 0 to 500. When the AQI reaches 101, the air is considered unhealthy for sensitive groups, including children and older adults. An AQI above 150 indicates the air can be unhealthy for the general public. While the average annual AQI score in the U.S. has been in the single digits in six of the last seven years, the effects of the Canadian wildfires have pushed the AQI well into the triple digits in parts of the country – making some major American cities among the most polluted in the world.

Using data from IQAir, Climate Crisis 247 identified the 10 major cities worldwide with the most polluted air. Major cities, including those in the U.S., are ranked on their AQI score as of August 1, 2025. AQI scores are updated in real-time and the numbers in this story offer a snapshot of air quality at midday.

The 10 most polluted cities in the world on August 1, 2025 have AQI scores ranging from 103 to 174. Most of the cities on this list are located in the Eastern Hemisphere, with two U.S. cities standing out as notable exceptions. These cities span nine countries and are collectively home to an estimated 73.4 million people, including over 3.1 million Americans.

10. Baghdad, Iraq

Photo by waqed walid on Pexels

  • Air Quality Index score on August 1, 2025: 103 out of 500 (Unhealthy for sensitive groups)
  • Estimated population: 7.9 million
  • Global region: Middle East
 

9. Tashkent, Uzbekistan

Photo by Farhodjon Chinberdiev on Unsplash

  • Air Quality Index score on August 1, 2025: 104 out of 500 (Unhealthy for sensitive groups)
  • Estimated population: 3.0 million
  • Global region: Central Asia
 

8. Incheon, South Korea

Photo by Hon Kim on Unsplash

  • Air Quality Index score on August 1, 2025: 105 out of 500 (Unhealthy for sensitive groups)
  • Estimated population: 3.0 million
  • Global region: East Asia
 

7. Dhaka, Bangladesh

Photo by Ahmed Hasan on Unsplash

  • Air Quality Index score on August 1, 2025: 106 out of 500 (Unhealthy for sensitive groups)
  • Estimated population: 10.2 million
  • Global region: South Asia
 

6. Beijing, China

Photo by Julius Carmine on Unsplash

  • Air Quality Index score on August 1, 2025: 117 out of 500 (Unhealthy for sensitive groups)
  • Estimated population: 22.6 million
  • Global region: East Asia
 

5. Chicago, Illinois

Photo by Ozzie Stern on Unsplash

  • Air Quality Index score on August 1, 2025: 126 out of 500 (Unhealthy for sensitive groups)
  • Estimated population: 2.7 million
  • Global region: North America
 

4. Kampala, Uganda

Photo by Frostee Lens Ug on Pexels

  • Air Quality Index score on August 1, 2025: 127 out of 500 (Unhealthy for sensitive groups)
  • Estimated population: 1.9 million
  • Global region: East Africa
 

3. Dubai, United Arab Emirates

Photo by Kate Trysh on Pexels

  • Air Quality Index score on August 1, 2025: 142 out of 500 (Unhealthy for sensitive groups)
  • Estimated population: 3.9 million
  • Global region: Middle East
 

2. Minneapolis, Minnesota

Photo by Josh Hild on Pexels

  • Air Quality Index score on August 1, 2025: 156 out of 500 (Unhealthy for the general public)
  • Estimated population: 428,579
  • Global region: North America
 

1. Kinshasa, Democratic Republic of the Congo

Photo by Kaysha on Unsplash

  • Air Quality Index score on August 1, 2025: 174 out of 500 (Unhealthy for the general public)
  • Estimated population: 17.8 million
  • Global region: Central Africa