SmogRank / History / Country race
Countries, worst air first, day by day
Each country's typical measured city over the 30 days to every day since January 2023, worst first. Press Play to watch the order change, or drag the slider to any day.
The worst countries for PM2.5 over the 7 days to 7 Nov 2025: Pakistan 135.4 µg/m³, India 43.0 µg/m³ and Bosnia and Herzegovina 33.0 µg/m³.
- 1Pakistan11 cities135.4
- 2India217 cities43.0
- 3Bosnia and Herzegovina5 cities33.0
- 4Peru6 cities29.6
- 5North Macedonia13 cities24.5
- 6Poland56 cities20.2
- 7Ghana3 cities19.9
- 8Mexico52 cities19.3
- 9Philippines3 cities19.3
- 10South Korea141 cities18.8
- 11Chile40 cities18.5
- 12Romania10 cities17.7
- 13Hong Kong13 cities16.5
- 14Hungary10 cities13.0
- 15Bulgaria7 cities12.4
- 16Slovakia32 cities12.1
- 17Kosovo8 cities12.0
- 18Latvia4 cities11.1
- 19Austria37 cities10.3
- 20Greece7 cities10.2
+ 22 more countries, 9.9 µg/m³ and below
- 30United States855 cities6.2
Not counted on this day, too few cities measured: Luxembourg since 7 Nov 2025, Czechia since 6 Nov 2025, Lithuania since 29 Oct 2025 and 6 more countries.
Countries counted each day
A country's number is its typical measured city: the median of its cities' means over the 30 days (a city needs 21 of them measured; 5 of 7 on the 7-day race), shown only with 3 such cities. A country whose monitors go quiet fades out where it stood rather than sliding down, so a gap never reads as cleaner air; "was" beside a city count marks a month after many cities joined or left. Some large countries are thin or missing because their monitors' licences don't allow reuse. How we rank.
Not covered: the government monitoring networks of China and Turkey, which publish only on their own websites; we are building the readers for them. Most cities there are missing from this board, not clean. Why.