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 19 Sep 2025: Pakistan 44.7 µg/m³, Peru 42.6 µg/m³ and Chile 24.2 µg/m³.
- 1Pakistan11 cities44.7
- 2Peru5 cities42.6
- 3Chile46 cities24.2
- 4India218 cities23.3
- 5Ghana4 cities23.2
- 6Philippines3 cities17.9
- 7Thailand68 cities10.9
- 8Brazil3 cities10.5
- 9Taiwan45 cities10.0
- 10Italy30 cities9.4
- 11Mexico46 cities9.2
- 12Serbia36 cities9.0
- 13Spain125 cities8.5
- 14Japan549 cities8.3
- 15Malta5 cities7.8
- 16Hungary10 cities, was 127.7
- 17United States870 cities7.7
- 18South Korea141 cities7.2
- 19Poland74 cities7.2
- 20Bosnia and Herzegovina5 cities7.0
+ 30 more countries, 6.9 µg/m³ and below
Not counted on this day, too few cities measured: China since 7 Aug 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.