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 15 Apr 2026: Laos 95.9 µg/m³, Kazakhstan 38.6 µg/m³ and Pakistan 38.6 µg/m³.
- 1Laos3 cities95.9
- 2Kazakhstan4 cities38.6
- 3Pakistan12 cities38.6
- 4India242 cities34.4
- 5Thailand83 cities31.6
- 6South Korea141 cities24.3
- 7Chile47 cities23.8
- 8Peru6 cities23.8
- 9Serbia4 cities18.5
- 10Taiwan44 cities17.9
- 11Poland59 cities17.7
- 12Mexico54 cities16.8
- 13Hong Kong13 cities14.5
- 14North Macedonia14 cities14.1
- 15Romania29 cities13.7
- 16Malta5 cities13.6
- 17Slovakia42 cities13.1
- 18Latvia4 cities12.6
- 19Hungary13 cities12.4
- 20Japan573 cities11.3
+ 26 more countries, the next at 11.3 µg/m³
- 40United States870 cities6.8
Not counted on this day, too few cities measured: Ghana since 15 Apr 2026, Bosnia and Herzegovina since 13 Apr 2026, Philippines since 8 Apr 2026 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 reader for China's network. Turkey's network doesn't answer requests from outside the country, so we can't read it. Most cities there are missing from this board, not clean. Why.