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 1 Sep 2026: Malawi 46.1 µg/m³, Chile 33.1 µg/m³ and Pakistan 33.1 µg/m³.
- 1Malawi5 cities46.1
- 2Chile47 cities33.1
- 3Pakistan14 cities33.1
- 4Lebanon3 cities25.8
- 5Nepal3 cities24.0
- 6South Africa18 cities22.3
- 7India206 cities21.3
- 8Montenegro4 cities15.5
- 9Mexico48 cities15.5
- 10North Macedonia14 cities13.9
- 11Italy31 cities13.3
- 12Serbia8 cities12.8
- 13Kazakhstan4 cities12.7
- 14Greece6 cities11.5
- 15Hong Kong12 cities11.5
- 16Brazil6 cities11.2
- 17Romania25 cities10.4
- 18Thailand76 cities10.2
- 19South Korea122 cities10.1
- 20Slovakia42 cities9.9
+ 27 more countries, 9.7 µg/m³ and below
- 25United States866 cities8.5
Not counted on this day, too few cities measured: Martinique since 27 Aug 2026, Bosnia and Herzegovina since 16 Aug 2026, Malta since 12 Aug 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.