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 14 Sep 2025: Pakistan 44.3 µg/m³, Peru 35.3 µg/m³ and Ghana 31.2 µg/m³.
- 1Pakistan11 cities44.3
- 2Peru5 cities35.3
- 3Ghana3 cities31.2
- 4India222 cities23.4
- 5Chile45 cities23.2
- 6Philippines3 cities21.1
- 7Serbia37 cities13.6
- 8Hungary4 cities, was 1211.5
- 9Greece9 cities10.8
- 10Poland74 cities10.8
- 11Bosnia and Herzegovina5 cities10.5
- 12Thailand66 cities10.5
- 13Mexico45 cities10.2
- 14Italy31 cities9.8
- 15Romania10 cities9.4
- 16Brazil3 cities9.1
- 17Latvia4 cities9.0
- 18Malta5 cities8.8
- 19South Korea140 cities8.6
- 20Bulgaria7 cities8.0
+ 28 more countries, 7.9 µg/m³ and below
- 30United States844 cities6.5
Not counted on this day, too few cities measured: Lithuania since 30 Aug 2025, Luxembourg since 23 Aug 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.