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The Most (and the Least) Polluted Cities in the World

Tracking the levels of tiny particulates that can cause respiratory health issues, IQ Air spills the beans on the most polluted cities around the globe.

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polluted city
Liyao Xie/Getty Images

IQAir, an organization that develops technology to help protect people from airborne pollution, recently released its 2020 world air quality report that shows the most polluted cities on the planet. Before we dive into rankings, it’s important to note that over 90 percent of the world breathes polluted air, making it our largest environmental health hazard. With everything shutting down due to the coronavirus pandemic, it seemed the environment was bouncing back, and while the short-lived decrease in fossil fuels ultimately did decrease air pollution, studies show that existing polluted air made people more susceptible to the virus and its health consequences. Luckily, there are small everyday changes we can make in order to prevent further damage to our planet’s air supply, such as investing in some eco-friendly products and learning which disposables to stop buying. And if you need some more convincing, these powerful photos prove that Earth still needs our help.

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Armed police walk on the Unity Square in downtown Hotan (Hetian), Xinjiang Uygur Autonomous Region. The statue at the back shows Chairman Mao Zedong shaking hands with a common Uygur old man Kuerban, a moment happenedd in Beijing in 1958. 06JUL13 == Pho
South China Morning Post/Getty Images

Most polluted: Hotan, China

Earning the top spot as the most polluted city is Hotan in western China, the only place in the top 10 most polluted cities not located in India. In this region of Xinjiang, there is a lot of coal burning and coal production. On top of that, the natural elements aren’t kind to residents. Along with the usual harms from development and population growth, Hotan—according to a report from the China Environmental Health Project—experiences sand-filled wind more than 300 days out of the year.

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Cityscape of Indirapuram. A Residential Hub in Ghaziabad (Delhi NCR) - Evening View
chander prakash joshi/Getty Images

Most polluted: Ghaziabad, India

The second most polluted city in the world is found in India, along with the rest of the top 14. Part of the capital region of Delhi, Ghaziabad had been the top most polluted city over the past couple of years and has finally been knocked down a peg. The city’s levels of traffic and industry play a large part in its pollution levels, but the most prominent factor is its urban topography, leading to massive amounts of dust accumulating in the city without a place to disperse. This second-place ranking is followed by other cities in India, including Bulandshahr, Bisrakh Jalalpur, and Bhiwadi.

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Elevated View of Kashgar Old Town in Xinjiang / Kashgar, Xinjiang
Zhenjin Li/Getty Images

Most polluted: Kashgar, China

Ranking number 15 after an abundance of cities in India, Kashgar has air that is considered hazardous to human life. Like Hotan, Kashgar is also in the Xinjiang region of China, so they experience unruly sandstorms, as well as water pollution and ecological damage. This makes Kashgar not only one of the most polluted cities, but one of the unhealthiest regions in the world.

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(EDITORS NOTE: Image taken with a drone) Aerial view of...
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Most polluted: Manikganj, Bangladesh

While India has the greatest number of polluted cities, its neighbor Bangladesh manages to have incredibly high levels of air pollution despite a much smaller population. Trends contributing to air pollution in South Asia include urbanization, economic growth, and industrialization.

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Wazir Khan Mosque, Lahore, Pakistan
HomoCosmicos/Getty Images

Most polluted: Lahore, Pakistan

Lahore makes a repeated appearance on IQAir’s live pollution rankings after flying under the radar until 2017, when Pakistan’s air quality data was published for the first time. When Pakistanis learned about their dangerous air quality issues, they began circulating a petition to review the government’s response to the smog crisis. According to IQAir, the court ordered authorities to prepare a smog response action plan and publish daily pollution updates.

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Diamond Head Waikiki Honolulu
Fiona Lin/Shutterstock

Least polluted: Honolulu, Hawaii

On a positive note, the American Lung Association in 2018 cited Hawaii—especially Honolulu—as having some of the cleanest air in the United States and anywhere else. The environmental website Mother Nature News points to Hawaii’s trade winds that carry air particulates out to sea. There are also very few industry operations based in Honolulu, and since the islands are isolated, there aren’t any hazardous particles blowing over from the mainland.

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Scenery of old town of Zurich, Switzerland from University hill.

Least polluted: Zurich, Switzerland

The city of Zurich is another city recognized for its clean air, and that’s by design: Its citizens largely cycle and use trains, buses, and subways instead of driving. The city has also implemented strict waste management techniques—they actually provide an app that helps residents track and manage their garbage and recycling.

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Stockholm cityscape
Johner Images/Getty Images

Least polluted: Stockholm, Sweden

Over the years, the air quality in Stockholm has improved greatly as the city has reduced the amount of hazardous pollutants being emitted into the air. Stockholm has reigned in emission requirements for vehicles and industries, and has introduced electric cars and environmental zones, according to IQAir. Stockholm also has a congestion tax in effect to assist in creating a cleaner environment within the city.

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Skyscrapers in downtown Calgary, Canada
Andrew Zarivny/Shutterstock

Least polluted: Calgary, Canada

Calgary is one of the cleanest cities in the world largely because of its approach to waste and waste management. Their “Too Good To Waste” campaign, for example, has reduced the amount of garbage going to landfills: Through sorting out compost and recyclables, the city has cut landfill waste in half, officials say.

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Helsinki cityscape with Helsinki Cathedral, Market Square (Kauppatori), Finland
Subodh Agnihotri/Shutterstock

Least polluted: Helsinki, Finland

The IQ Air report lists the capital of Finland as one of the least polluted capital cities in the world. One reason, according to The Telegraph, is that residents routinely use public transportation and bicycles to get around; the city makes it easy by maintaining roughly 2,400 miles worth of cycle lanes.


  • IQAir: “Global map of PM2.5 exposure by city in 2020”
  • IQAir: “World’s most polluted cities 2020 (PM2.5)”
  • Circle of Blue: “Environmental Health Challenges in Xinjiang”
  • Wilson Center: “Environmental Health Challenges in Xinjiang”
  • American Lung Association: “Hawaii Boasts Some of the Best Air Quality in the Nation According to the ‘State of the Air’ 2019 Report”
  • Treehugger: “8 Cities Where Cleanliness Rules”
  • Telegraph: “The 10 cleanest capital cities on Earth”
  • Calgary: “Waste and Recycling Education Resources”
  • SWI: “What does it take to keep Swiss streets so clean?”
  • IQAir: “Air quality in Stockholm”

Taylor Markarian
Taylor Markarian is a regular contributor to RD.com covering culture, advice, travel, pets and all things weird and haunted. She is the author of "From the Basement: A History of Emo Music and How It Changed Society," which analyzes the evolution of punk and mental health. She holds a B.A. in Writing, Literature and Publishing from Emerson College.
Emma Taubenfeld
Emma Taubenfeld is a former assistant editor for Reader’s Digest who writes about digital lifestyle topics such as memes, social media captions, pickup lines and cute pets. When she’s not working, you can find Emma reading corny young adult novels, creating carefully curated playlists and figuring out how to spice up boxed mac and cheese.