Air pollution is one of the leading causes of death around the world. Therefore you may be curious: What are the least polluted cities in the world? And what is the least polluted country in the world? Smart Air analyzed 2022 air pollution data from 529 major cities spanning 88 countries in the world to create the 2022 ranking of the “25 Least Polluted Cities in the World”. So, which cities and countries had the best air quality?
Rankings: 25 Least Polluted Cities in the World
The rankings for the least polluted cities in the world are based on PM2.5 air pollution data from the 12 months prior to the publication date.
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Read on for the full list of 25 cities with the best air quality in the world and an analysis of what this data means.
1. Zurich, Switzerland (0.46 µg/m3)

2. Hobart, Australia (2.55 µg/m3)

3. Launceston, Australia (3.33 µg/m3)

4. Vancouver, Canada (3.60 µg/m3)

5. Honolulu, US (3.78 µg/m3)

6. Wollongong, Australia (4.12 µg/m3)

7. Reykjavík, Iceland (4.13 µg/m3)

8. Vitória, Brazil (4.24 µg/m3)

9. Turku, Finland (4.35 µg/m3)

10. Uppsala, Sweden (4.64 µg/m3)

11. Tampere, Finland (4.75 µg/m3)

12. Haiphong, Vietnam (4.76 µg/m3)

13. Oulu, Finland (4.85 µg/m3)

14. Sydney, Australia (4.90 µg/m3)

15. Castellón de la Plana, Spain (4.95 µg/m3)

16. Trondheim, Norway (4.95 µg/m3)

17. Portland, US (4.98 µg/m3)

18. Salem, US (5.00 µg/m3)

19. Newcastle, Australia (5.01 µg/m3)

20. Halifax, Canada (5.01 µg/m3)

21. Surrey, Canada (5.03 µg/m3)

22. Adelaide, Australia (5.10 µg/m3)

23. Tallinn, Estonia (5.13 µg/m3)

24. Brisbane, Australia (5.18 µg/m3)

25. Bergen, Norway (5.29 µg/m3)

Read More: The 25 Most Polluted Cities of 2022?
What is the Least Polluted Country in the World?
Australia topped the list as the least polluted country in the world, with 7 cities in the top 25. Of the 25 least polluted cities in the world with the best air quality, Nordic countries (Finland, Sweden, Norway, Iceland) dominated the rankings with some of the cleanest air in the world in 2022.
14 out of the 25 cities with the best and cleanest air were either in Nordic countries or Australia. Zurich, Switzerland once again ranked as the least polluted city in the world. Australia, Canada, and Finland were the only countries having at least 3 cities ranking in the top 25 least polluted cities in the world.
Compared with the last rankings update 6 months ago, Australian cities saw an improvement in rankings with only 2 cities. On the other hand, Nordic countries saw a drop in the number of cities from 10 to 8.
Even though these are some of the cities with the best air quality in the world, each city experienced times when air pollution was over the WHO recommended limit. Only 17 out of 25 of these cities met the new WHO air quality guidelines (AQG) levels of 5 µg/m3. This shows how serious air pollution is all across the world. There is also research that even little amounts of pollution such as those typically present in these least polluted cities can have an impact on health.
Below is a pollution heat map from the WHO. WHO research shows that over 99% of people in the world are breathing unsafe air with high air pollution levels.

How Air Pollution Was Measured to Find Least Polluted Cities in World
The above rankings of the 2022 least polluted cities in the world were ranked based on their average PM2.5 pollution levels from the 12 months prior to the publication date.
These small pollutants are under 2.5 micrograms in width and are considered to be one of the more dangerous pollutants due to their ability to enter deep into the lungs and bloodstream.
Open Data
The raw PM2.5 AQI 2021 world pollution data used for the rankings of the world’s least polluted cities are openly available to download from aqicn.org.
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