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 24 May 2026: Chile 42.8 µg/m³, Pakistan 42.4 µg/m³ and India 33.3 µg/m³.
- 1Chile46 cities42.8
- 2Pakistan14 cities42.4
- 3India212 cities33.3
- 4Peru6 cities29.8
- 5Laos3 cities21.7
- 6Mexico41 cities19.1
- 7Malawi5 cities18.6
- 8Thailand79 cities18.1
- 9Kazakhstan4 cities16.7
- 10South Korea137 cities14.1
- 11Lebanon3 cities13.7
- 12Taiwan44 cities12.5
- 13Malta5 cities12.0
- 14Hong Kong13 cities11.8
- 15Serbia8 cities11.7
- 16New Zealand6 cities11.1
- 17Senegal3 cities11.1
- 18Brazil6 cities10.7
- 19North Macedonia14 cities9.8
- 20Greece5 cities9.2
+ 28 more countries, 9.0 µg/m³ and below
- 36United States869 cities5.5
Not counted on this day, too few cities measured: Slovenia since 19 May 2026, Lithuania since 12 May 2026, Poland since 23 Apr 2026 and 3 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 readers for them. Most cities there are missing from this board, not clean. Why.