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 30 days to 9 Oct 2025: Pakistan 58.0 µg/m³, Peru 31.9 µg/m³ and India 23.7 µg/m³.
- 1Pakistan11 cities58.0
- 2Peru5 cities31.9
- 3India218 cities23.7
- 4Chile46 cities22.5
- 5Philippines3 cities19.8
- 6Ghana4 cities18.6
- 7Serbia38 cities13.1
- 8Mexico47 cities11.0
- 9Bosnia and Herzegovina5 cities10.9
- 10Taiwan45 cities10.7
- 11Thailand76 cities10.3
- 12Poland72 cities10.0
- 13Italy18 cities9.6
- 14Brazil3 cities8.9
- 15Hungary8 cities8.7
- 16Latvia4 cities8.5
- 17South Korea141 cities8.2
- 18Spain107 cities7.9
- 19Romania11 cities7.9
- 20Hong Kong13 cities7.8
+ 27 more countries, 7.6 µg/m³ and below
- 27United States878 cities6.8
Not counted on this day, too few cities measured: Austria since 8 Oct 2025, Greece since 8 Oct 2025 and Czechia since 18 Sep 2025.
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.