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 6 May 2026: Pakistan 35.6 µg/m³, Chile 33.9 µg/m³ and Peru 30.9 µg/m³.
- 1Pakistan14 cities35.6
- 2Chile47 cities33.9
- 3Peru6 cities30.9
- 4Laos3 cities27.8
- 5India174 cities27.2
- 6Thailand81 cities21.2
- 7Malawi5 cities20.6
- 8Mexico48 cities19.9
- 9Kazakhstan4 cities17.2
- 10South Korea137 cities14.8
- 11Lebanon3 cities12.5
- 12Serbia8 cities12.3
- 13New Zealand6 cities11.5
- 14Taiwan44 cities11.4
- 15Hong Kong12 cities11.3
- 16Romania27 cities10.3
- 17Senegal3 cities10.1
- 18Malta5 cities9.9
- 19United Kingdom5 cities9.8
- 20Slovakia42 cities9.6
+ 30 more countries, 9.5 µg/m³ and below
- 40United States849 cities5.3
Not counted on this day, too few cities measured: Czechia since 6 May 2026, Poland since 16 Apr 2026, Ghana since 8 Apr 2026 and 2 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.