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 3 Apr 2026: Laos 97.8 µg/m³, Kazakhstan 45.9 µg/m³ and Pakistan 34.5 µg/m³.
- 1Laos3 cities97.8
- 2Kazakhstan4 cities45.9
- 3Pakistan13 cities34.5
- 4India238 cities31.6
- 5Thailand85 cities27.7
- 6South Korea141 cities26.9
- 7Ghana3 cities26.0
- 8Peru6 cities24.7
- 9Chile46 cities23.5
- 10Taiwan44 cities19.3
- 11Serbia4 cities17.3
- 12Senegal4 cities16.2
- 13Hong Kong13 cities15.7
- 14Mexico52 cities15.6
- 15Poland60 cities15.4
- 16Latvia3 cities14.6
- 17Japan574 cities12.2
- 18Hungary13 cities11.7
- 19North Macedonia13 cities11.5
- 20Slovakia42 cities11.3
+ 30 more countries, 10.8 µg/m³ and below
- 36United States870 cities6.5
Not counted on this day, too few cities measured: Philippines since 28 Mar 2026, Kyrgyzstan since 25 Mar 2026, Czechia since 18 Mar 2026 and Spain since 11 Feb 2026.
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.