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 15 Aug 2026: Malawi 37.4 µg/m³, Pakistan 37.4 µg/m³ and Chile 37.2 µg/m³.
- 1Malawi5 cities37.4
- 2Pakistan15 cities37.4
- 3Chile45 cities37.2
- 4Lebanon3 cities26.8
- 5Nepal3 cities21.3
- 6India227 cities20.8
- 7Hong Kong12 cities15.7
- 8Mexico45 cities15.7
- 9Italy33 cities14.7
- 10Taiwan44 cities12.4
- 11Kazakhstan4 cities12.3
- 12North Macedonia14 cities12.3
- 13Spain79 cities11.9
- 14Serbia8 cities11.8
- 15Montenegro4 cities11.0
- 16Greece10 cities10.9
- 17Slovakia40 cities9.8
- 18Thailand75 cities9.8
- 19Switzerland11 cities, was 39.1
- 20Brazil6 cities8.8
+ 26 more countries, 8.7 µg/m³ and below
- 23United States857 cities8.5
Not counted on this day, too few cities measured: Bosnia and Herzegovina since 12 Aug 2026, Lithuania since 12 Aug 2026, Martinique since 12 Aug 2026 and 5 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.