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 7 Apr 2026: Laos 72.9 µg/m³, Kazakhstan 47.4 µg/m³ and Pakistan 43.5 µg/m³.
- 1Laos3 cities72.9
- 2Kazakhstan4 cities47.4
- 3Pakistan12 cities43.5
- 4India239 cities36.8
- 5Thailand84 cities29.9
- 6South Korea141 cities27.6
- 7Peru6 cities23.2
- 8Ghana3 cities22.1
- 9Chile47 cities20.9
- 10Poland59 cities20.3
- 11Philippines3 cities19.8
- 12Latvia4 cities19.4
- 13Serbia4 cities18.7
- 14Taiwan44 cities17.5
- 15North Macedonia14 cities17.3
- 16Mexico50 cities16.8
- 17Hong Kong13 cities16.5
- 18Bosnia and Herzegovina6 cities15.8
- 19Romania28 cities15.1
- 20Hungary13 cities14.0
+ 29 more countries, 13.7 µg/m³ and below
- 44United States872 cities6.5
Not counted on this day, too few cities measured: 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.