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 9 Apr 2026: Laos 77.9 µg/m³, Kazakhstan 45.7 µg/m³ and Pakistan 39.8 µg/m³.
- 1Laos3 cities77.9
- 2Kazakhstan4 cities45.7
- 3Pakistan12 cities39.8
- 4India243 cities35.8
- 5Thailand85 cities30.2
- 6South Korea141 cities26.1
- 7Peru6 cities23.1
- 8Chile48 cities21.4
- 9Ghana3 cities21.2
- 10Serbia4 cities19.0
- 11Poland59 cities18.7
- 12Taiwan44 cities17.6
- 13Latvia4 cities16.9
- 14Mexico53 cities16.6
- 15North Macedonia14 cities16.5
- 16Hong Kong13 cities16.3
- 17Bosnia and Herzegovina6 cities14.4
- 18Romania28 cities14.3
- 19Hungary13 cities13.1
- 20Slovakia42 cities13.0
+ 28 more countries, 12.6 µg/m³ and below
- 42United States871 cities6.4
Not counted on this day, too few cities measured: Philippines since 8 Apr 2026, Kyrgyzstan since 5 Apr 2026 and Spain since 18 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.