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 Feb 2025: Pakistan 93.5 µg/m³, India 92.0 µg/m³ and Thailand 49.6 µg/m³.
- 1Pakistan4 cities93.5
- 2India5 cities92.0
- 3Thailand16 cities49.6
- 4Serbia14 cities39.1
- 5China4 cities38.8
- 6Romania9 cities27.1
- 7Slovenia12 cities27.0
- 8Bulgaria5 cities25.7
- 9Poland75 cities25.4
- 10South Korea141 cities22.3
- 11Hungary9 cities22.2
- 12Slovakia42 cities20.5
- 13Hong Kong13 cities19.3
- 14Croatia3 cities18.9
- 15Belgium45 cities18.5
- 16Chile46 cities18.1
- 17The Netherlands23 cities17.8
- 18Austria36 cities17.6
- 19Mexico13 cities17.1
- 20Peru5 cities, was 1516.9
+ 21 more countries, 16.1 µg/m³ and below
- 33United States815 cities7.4
Not counted on this day, too few cities measured: Luxembourg since 2 Feb 2025, Czechia since 18 Jan 2025, Singapore since 16 Jan 2025 and 3 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.