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 27 Jan 2025: India 104.7 µg/m³, Bosnia and Herzegovina 96.2 µg/m³ and Pakistan 82.7 µg/m³.
- 1India5 cities104.7
- 2Bosnia and Herzegovina3 cities96.2
- 3Pakistan4 cities82.7
- 4Thailand16 cities67.4
- 5China3 cities49.8
- 6Serbia10 cities43.0
- 7Bulgaria8 cities35.7
- 8Romania10 cities34.5
- 9South Korea140 cities32.0
- 10Poland77 cities28.0
- 11Croatia4 cities26.2
- 12Slovakia42 cities21.7
- 13Hungary10 cities21.1
- 14Slovenia12 cities21.0
- 15Mexico17 cities19.7
- 16Taiwan43 cities19.4
- 17Greece9 cities, was 918.3
- 18Hong Kong13 cities17.7
- 19Peru5 cities, was 1617.4
- 20Chile43 cities17.3
+ 23 more countries, 16.7 µg/m³ and below
- 34United States800 cities7.7
Not counted on this day, too few cities measured: Sweden since 27 Jan 2025, Luxembourg since 21 Jan 2025, Lithuania since 13 Jan 2025 and 2 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.