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 9 May 2026: Pakistan 49.8 µg/m³, Chile 29.9 µg/m³ and Peru 28.2 µg/m³.
- 1Pakistan14 cities49.8
- 2Chile46 cities29.9
- 3Peru6 cities28.2
- 4India159 cities27.7
- 5Laos3 cities22.4
- 6Malawi5 cities20.8
- 7Mexico49 cities20.7
- 8Thailand81 cities20.1
- 9Malta4 cities17.8
- 10Kazakhstan4 cities15.4
- 11Lebanon3 cities13.9
- 12Serbia8 cities12.7
- 13Hong Kong11 cities11.9
- 14North Macedonia14 cities11.4
- 15South Korea131 cities11.1
- 16Romania28 cities11.1
- 17United Kingdom5 cities11.0
- 18Taiwan44 cities10.9
- 19Greece8 cities, was 129.8
- 20New Zealand6 cities9.6
+ 28 more countries, 9.5 µg/m³ and below
- 36United States863 cities5.6
Not counted on this day, too few cities measured: Estonia since 8 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.