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 13 Aug 2025: Pakistan 39.5 µg/m³, Chile 38.0 µg/m³ and Peru 26.1 µg/m³.
- 1Pakistan11 cities39.5
- 2Chile48 cities38.0
- 3Peru4 cities26.1
- 4Ghana4 cities24.0
- 5India227 cities22.8
- 6Philippines3 cities21.2
- 7Italy28 cities17.8
- 8Bosnia and Herzegovina4 cities15.3
- 9Switzerland11 cities14.1
- 10Spain112 cities14.0
- 11Mexico36 cities13.3
- 12Slovakia40 cities12.1
- 13Czechia18 cities11.4
- 14Malta5 cities11.3
- 15Brazil3 cities11.2
- 16Slovenia12 cities11.2
- 17Greece10 cities10.9
- 18South Korea140 cities10.4
- 19Belgium50 cities10.3
- 20Austria36 cities10.2
+ 25 more countries, 10.0 µg/m³ and below
- 34United States849 cities7.8
Not counted on this day, too few cities measured: Martinique since 9 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 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.