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 31 Aug 2026: Malawi 42.0 µg/m³, Pakistan 33.0 µg/m³ and Chile 32.9 µg/m³.
- 1Malawi5 cities42.0
- 2Pakistan14 cities33.0
- 3Chile47 cities32.9
- 4Lebanon3 cities25.6
- 5Nepal3 cities24.7
- 6India208 cities21.3
- 7Mexico48 cities15.4
- 8Montenegro4 cities15.3
- 9North Macedonia14 cities, was 413.7
- 10Italy32 cities13.5
- 11Kazakhstan4 cities12.6
- 12Serbia8 cities12.5
- 13Brazil6 cities11.5
- 14Greece6 cities11.4
- 15Hong Kong11 cities11.4
- 16South Korea124 cities10.5
- 17Romania23 cities10.5
- 18Slovakia41 cities10.3
- 19New Zealand6 cities10.2
- 20Thailand76 cities10.2
+ 25 more countries, 9.9 µg/m³ and below
- 25United States865 cities8.5
Not counted on this day, too few cities measured: Portugal since 29 Aug 2026, Martinique since 27 Aug 2026, Bosnia and Herzegovina since 16 Aug 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.