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 18 Aug 2025: Pakistan 40.8 µg/m³, Chile 33.9 µg/m³ and Peru 27.6 µg/m³.
- 1Pakistan11 cities40.8
- 2Chile48 cities33.9
- 3Peru5 cities27.6
- 4Philippines3 cities22.4
- 5India229 cities19.8
- 6Ghana4 cities17.8
- 7Italy27 cities16.8
- 8Switzerland11 cities16.3
- 9Malta5 cities16.2
- 10Spain86 cities15.9
- 11Brazil49 cities15.4
- 12Czechia33 cities15.2
- 13New Zealand10 cities14.4
- 14Slovakia42 cities14.3
- 15Bosnia and Herzegovina4 cities14.1
- 16Slovenia12 cities13.3
- 17Mexico38 cities13.2
- 18Luxembourg3 cities11.9
- 19Austria36 cities11.8
- 20Germany230 cities11.6
+ 25 more countries, the next at 11.5 µg/m³
- 34United States857 cities7.4
Not counted on this day, too few cities measured: Martinique since 18 Aug 2025, China since 7 Aug 2025, Serbia since 3 Jul 2025 and 2 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, Turkey and Iran, which publish only on their own websites. We are building the reader for China's network. The networks of Turkey and Iran don't answer requests from outside their countries, so we can't read them. Most cities there are missing from this board, not clean. Why.