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 20 Mar 2025: India 35.7 µg/m³, Serbia 24.8 µg/m³ and Laos 24.7 µg/m³.
- 1India231 cities, was 535.7
- 2Serbia39 cities, was 1224.8
- 3Laos3 cities24.7
- 4Thailand86 cities24.6
- 5Mexico55 cities, was 1422.8
- 6Chile45 cities20.8
- 7South Korea141 cities19.9
- 8Poland71 cities18.9
- 9Peru6 cities18.6
- 10Taiwan44 cities17.1
- 11Hong Kong13 cities17.0
- 12Greece12 cities16.6
- 13Ireland5 cities14.7
- 14Hungary4 cities13.4
- 15Romania10 cities13.0
- 16United Kingdom6 cities11.8
- 17France105 cities, was 2311.2
- 18Slovakia42 cities10.8
- 19Germany236 cities10.3
- 20Austria37 cities10.1
+ 20 more countries, 10.1 µg/m³ and below
- 33United States836 cities6.5
Not counted on this day, too few cities measured: Lithuania since 20 Mar 2025, Bosnia and Herzegovina since 18 Mar 2025, Luxembourg since 15 Mar 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.