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 18 Feb 2025: India 87.0 µg/m³, Pakistan 77.3 µg/m³ and Bosnia and Herzegovina 69.1 µg/m³.
- 1India5 cities87.0
- 2Pakistan4 cities77.3
- 3Bosnia and Herzegovina3 cities69.1
- 4Thailand72 cities, was 1644.4
- 5Serbia19 cities41.4
- 6China4 cities36.8
- 7Poland76 cities29.4
- 8Slovenia12 cities28.2
- 9Romania8 cities28.1
- 10Bulgaria5 cities25.1
- 11Czechia19 cities, was 3623.4
- 12Hungary11 cities22.0
- 13South Korea141 cities21.8
- 14Slovakia42 cities21.1
- 15Chile45 cities19.7
- 16Hong Kong13 cities19.4
- 17Belgium45 cities19.3
- 18Croatia3 cities19.3
- 19The Netherlands23 cities19.3
- 20Austria36 cities18.3
+ 25 more countries, 17.5 µg/m³ and below
- 37United States822 cities7.2
Not counted on this day, too few cities measured: Luxembourg since 2 Feb 2025 and Singapore since 16 Jan 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.