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 15 Sep 2025: Pakistan 45.3 µg/m³, Peru 36.9 µg/m³ and Ghana 26.2 µg/m³.
- 1Pakistan11 cities45.3
- 2Peru5 cities36.9
- 3Ghana4 cities26.2
- 4Chile44 cities24.3
- 5India225 cities24.2
- 6Philippines3 cities23.4
- 7Serbia38 cities13.2
- 8Hungary4 cities, was 1211.2
- 9Thailand68 cities10.9
- 10Greece9 cities10.7
- 11Poland73 cities10.0
- 12Brazil3 cities9.7
- 13Italy31 cities9.3
- 14Mexico46 cities9.1
- 15Bosnia and Herzegovina5 cities8.9
- 16Latvia4 cities8.6
- 17Romania11 cities8.6
- 18South Korea141 cities8.5
- 19Malta5 cities8.4
- 20Japan545 cities7.7
+ 28 more countries, 7.7 µg/m³ and below
- 27United States864 cities6.9
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.