Where is the air most polluted?
Click any country to see its average exposure to fine particulate matter (PM2.5) — the most harmful form of air pollution.
Overview
Fine particulate matter (PM2.5) is the air pollutant most damaging to health, penetrating deep into the lungs. This map shows average population exposure for every country, in micrograms per cubic metre.
Key facts
- The WHO guideline is an annual average of 5 µg/m³.
- The most polluted countries exceed 50 µg/m³ — ten times the guideline.
- Air pollution is a leading environmental cause of death.
Common questions
What is PM2.5?
Fine particulate matter less than 2.5 micrometres across — small enough to reach deep into the lungs and bloodstream. It is the air pollutant most closely linked to ill health.
What level is safe?
The WHO recommends an annual average below 5 µg/m³. Much of the world's population lives well above that.
Where does the data come from?
WHO and satellite-derived estimates of population-weighted PM2.5 exposure, compiled via Our World in Data.
Sources & methodology
Data from WHO (via Our World in Data), compiled via Our World in Data. Global figures are population-weighted across the countries that report this measure; countries without reliable recent data are shown as “no data”.
Last updated: 3 August 2026.
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