LIVE • 2026-09-20
Cleanest air cities right now
Top 30 cities with the cleanest air across all 217 tracked locations, ranked by US EPA Air Quality Index. Refreshes every 30 minutes. The cleanest right now is Quito, Ecuador at AQI 9 (Good). PM2.5 there is 1.8 μg/m³ (below the WHO 2021 annual guideline of 5 μg/m³.
What makes a city “clean”
Cities that consistently rank near the top share a few patterns: low population density and limited heavy industry, prevailing winds that flush pollutants out to ocean or open terrain, mild summers that suppress ozone formation, mature emissions controls on vehicles and power generation, and minimal exposure to long-range smoke transport. Coastal Nordic, Atlantic Canadian, Oceania, and high-altitude South American cities dominate this list.
Ranking caveats
A momentary AQI snapshot can swing with weather. A clean city might briefly spike during a wildfire event or summer ozone day; a polluted city can dip after a rain wash-out. For a fair comparison, look at the city page’s readings over multiple checks. See methodology for full detail.
See also: most polluted today · PM2.5 guide · methodology.