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 10 Nov 2025: Pakistan 127.8 µg/m³, India 49.1 µg/m³ and Bosnia and Herzegovina 28.6 µg/m³.
- 1Pakistan11 cities127.8
- 2India219 cities49.1
- 3Bosnia and Herzegovina5 cities28.6
- 4Peru6 cities28.6
- 5North Macedonia13 cities21.4
- 6Chile35 cities18.9
- 7Philippines3 cities17.5
- 8Mexico45 cities17.3
- 9Hong Kong13 cities15.2
- 10Romania10 cities14.8
- 11Poland59 cities14.5
- 12Slovakia10 cities, was 4212.7
- 13Kosovo7 cities12.3
- 14South Korea141 cities12.2
- 15Bulgaria8 cities12.0
- 16Hungary12 cities, was 1211.8
- 17Latvia4 cities11.8
- 18Montenegro5 cities10.1
- 19Slovenia11 cities9.5
- 20Switzerland10 cities7.6
+ 18 more countries, 7.5 µg/m³ and below
- 30United States874 cities5.6
Not counted on this day, too few cities measured: Lithuania since 31 Oct 2025, Brazil since 23 Oct 2025, Thailand since 20 Oct 2025 and 10 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.