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 26 Sep 2025: Pakistan 56.0 µg/m³, Peru 29.5 µg/m³ and India 25.0 µg/m³.
- 1Pakistan11 cities56.0
- 2Peru5 cities29.5
- 3India215 cities25.0
- 4Chile46 cities20.7
- 5Ghana4 cities15.7
- 6Philippines3 cities12.6
- 7Mexico48 cities10.9
- 8Serbia39 cities10.3
- 9North Macedonia12 cities9.8
- 10Italy28 cities9.6
- 11Bosnia and Herzegovina5 cities9.5
- 12Thailand77 cities9.4
- 13Brazil3 cities9.2
- 14Hong Kong11 cities8.5
- 15Hungary9 cities, was 128.2
- 16Montenegro5 cities7.8
- 17Latvia4 cities7.7
- 18Romania11 cities7.7
- 19Taiwan44 cities7.7
- 20Czechia22 cities, was 37.4
+ 30 more countries, 7.4 µg/m³ and below
- 30United States869 cities6.5
Not counted on this day, too few cities measured: Greece since 25 Sep 2025 and China since 7 Aug 2025.
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.