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 8 Feb 2025: Pakistan 95.1 µg/m³, India 93.4 µg/m³ and Thailand 49.6 µg/m³.
- 1Pakistan4 cities95.1
- 2India5 cities93.4
- 3Thailand16 cities49.6
- 4Serbia14 cities39.3
- 5China4 cities38.7
- 6Romania10 cities27.9
- 7Slovenia12 cities24.2
- 8Poland75 cities23.4
- 9South Korea141 cities22.2
- 10Hungary9 cities21.1
- 11Hong Kong13 cities20.2
- 12Slovakia42 cities19.2
- 13Chile46 cities17.9
- 14Belgium45 cities17.4
- 15Mexico13 cities16.8
- 16Peru5 cities, was 1516.7
- 17Taiwan43 cities16.0
- 18Greece6 cities15.8
- 19Austria36 cities15.6
- 20The Netherlands23 cities15.6
+ 19 more countries, 15.1 µg/m³ and below
- 31United States805 cities7.5
Not counted on this day, too few cities measured: Bulgaria since 4 Feb 2025, Luxembourg since 2 Feb 2025, Czechia since 18 Jan 2025 and 5 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.