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 10 May 2026: Pakistan 53.5 µg/m³, Chile 30.1 µg/m³ and India 29.4 µg/m³.
- 1Pakistan15 cities53.5
- 2Chile45 cities30.1
- 3India159 cities29.4
- 4Peru6 cities26.6
- 5Mexico50 cities21.3
- 6Thailand79 cities20.4
- 7Laos3 cities19.5
- 8Malta4 cities19.3
- 9Malawi5 cities18.6
- 10Lebanon3 cities17.2
- 11Kazakhstan4 cities16.1
- 12Serbia8 cities13.3
- 13Hong Kong13 cities12.9
- 14North Macedonia14 cities11.8
- 15Greece7 cities, was 1210.6
- 16Romania28 cities10.6
- 17South Korea134 cities10.4
- 18Taiwan44 cities10.2
- 19Belgium52 cities10.0
- 20Slovakia42 cities9.4
+ 28 more countries, 9.2 µg/m³ and below
- 35United States854 cities5.6
Not counted on this day, too few cities measured: Senegal since 10 May 2026, Lithuania since 7 May 2026, Czechia since 6 May 2026 and 4 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.