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 5 Apr 2026: Laos 65.2 µg/m³, Kazakhstan 50.6 µg/m³ and Pakistan 48.7 µg/m³.
- 1Laos3 cities65.2
- 2Kazakhstan4 cities50.6
- 3Pakistan12 cities48.7
- 4India238 cities38.1
- 5Thailand84 cities28.7
- 6South Korea141 cities27.8
- 7Ghana3 cities23.4
- 8Peru6 cities22.9
- 9Poland59 cities22.5
- 10Latvia4 cities21.1
- 11Chile47 cities20.8
- 12Serbia4 cities19.9
- 13Philippines3 cities18.9
- 14North Macedonia14 cities18.6
- 15Mexico50 cities17.6
- 16Taiwan44 cities17.5
- 17Hong Kong13 cities17.0
- 18Bosnia and Herzegovina6 cities16.5
- 19Romania28 cities15.8
- 20Hungary13 cities15.3
+ 29 more countries, 14.7 µg/m³ and below
- 44United States875 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.