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 21 Sep 2026: Malawi 59.5 µg/m³, Pakistan 42.7 µg/m³ and Indonesia 31.0 µg/m³.
- 1Malawi5 cities59.5
- 2Pakistan14 cities42.7
- 3Indonesia4 cities31.0
- 4India224 cities, was 21225.4
- 5Philippines3 cities23.2
- 6Chile47 cities22.7
- 7South Africa38 cities17.5
- 8Hong Kong12 cities16.1
- 9Ghana3 cities16.0
- 10Serbia8 cities14.1
- 11Senegal4 cities13.8
- 12Mexico35 cities13.3
- 13Taiwan44 cities12.5
- 14Kazakhstan5 cities12.3
- 15Lebanon3 cities11.9
- 16Montenegro4 cities11.6
- 17North Macedonia15 cities10.6
- 18Romania25 cities10.0
- 19Thailand73 cities9.9
- 20South Korea131 cities9.4
+ 30 more countries, 8.7 µg/m³ and below
- 32United States897 cities5.8
Not counted on this day, too few cities measured: Nigeria since 20 Sep 2026, Bosnia and Herzegovina since 18 Sep 2026, Nepal since 14 Sep 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.