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 12 Oct 2025: Pakistan 52.6 µg/m³, India 36.0 µg/m³ and Peru 27.3 µg/m³.
- 1Pakistan11 cities52.6
- 2India228 cities36.0
- 3Peru5 cities27.3
- 4Chile45 cities19.5
- 5Bosnia and Herzegovina5 cities15.4
- 6North Macedonia13 cities13.9
- 7Hungary5 cities13.6
- 8Taiwan45 cities12.8
- 9Belgium49 cities12.5
- 10Thailand70 cities11.9
- 11Switzerland10 cities11.6
- 12Poland64 cities11.0
- 13France97 cities, was 1410.1
- 14Hong Kong13 cities9.8
- 15Mexico48 cities9.1
- 16Lithuania3 cities8.7
- 17Martinique3 cities8.6
- 18Slovenia12 cities8.5
- 19Australia22 cities8.3
- 20The Netherlands33 cities7.9
+ 20 more countries, 7.8 µg/m³ and below
- 36United States856 cities4.9
Not counted on this day, too few cities measured: Norway since 12 Oct 2025, Philippines since 12 Oct 2025, Serbia since 12 Oct 2025 and 8 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.