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 11 Jul 2025: Chile 50.4 µg/m³, Pakistan 40.3 µg/m³ and Peru 26.9 µg/m³.
- 1Chile46 cities50.4
- 2Pakistan9 cities40.3
- 3Peru5 cities26.9
- 4India205 cities22.1
- 5New Zealand10 cities14.6
- 6South Korea140 cities13.7
- 7Japan567 cities13.4
- 8Bosnia and Herzegovina5 cities12.4
- 9Italy7 cities, was 2012.2
- 10Mexico32 cities11.8
- 11Slovakia39 cities10.6
- 12Spain92 cities, was 8710.5
- 13Hungary4 cities, was 129.6
- 14Slovenia12 cities8.8
- 15United States837 cities8.5
- 16Romania10 cities7.9
- 17Poland59 cities7.8
- 18Bulgaria7 cities7.4
- 19Hong Kong13 cities7.3
- 20Austria37 cities7.2
+ 15 more countries, 7.0 µg/m³ and below
Not counted on this day, too few cities measured: Serbia since 10 Jul 2025, Thailand since 10 Jul 2025, Taiwan since 10 Jul 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.