Canberra has the best air quality of any major capital in the world, and Australia has the best air quality of any developed country bar Iceland.
That’s according to IQAir, which provides an annual report and global platform with real-time air quality data worldwide. Its 2025 Air Quality Report covers 9,446 cities across 143 countries.
At the highest end for air quality, Australia is closely followed by Estonia, New Zealand, Finland and Sweden. A number of Latin American countries also have excellent air quality: Panama, Costa Rica and Ecuador.
Air quality is commonly measured based on PM2.5 guidelines. This refers to the quantity of fine particulate matter of 2.5 micrometres in diametre or less.
These are of health concern because as very fine particles, they penetrate deeply into the lungs and may even enter the bloodstream. They are challenging for the body to adequately remove when they are being constantly inhaled.
The most common sources of PM2.5 are exhaust, dust, aerosols, smoke and fine metallic particles. For reference PM10 size includes coarse dust, pollen and mould spores.
The WHO guideline is for countries to endeavour to limit PM2.5 particles to 5 micrograms or less per cubic metre of air. Above 5 micrograms, negative health impacts accelerate.
“Globally, just 13 countries, regions, and territories saw annual average PM2.5 concentrations meeting the WHO annual PM2.5 guideline of 5 μg/m³,” said the IQ report, “with the majority located in the Latin America and Caribbean region.” The only ones that aren’t tropical tax havens are Australia, Estonia and Iceland.
The best capital cities in the world for air quality, aside from Canberra, are Wellington, Dublin, Oslo, Stockholm and Helsinki.
Of major countries, the worst air pollution can be found in India, Pakistan and Egypt. A number of Central Asian and Central African countries also have air quality at the lowest level.
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