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 27 Aug 2025: Pakistan 33.7 µg/m³, Chile 27.1 µg/m³ and Ghana 24.2 µg/m³.
- 1Pakistan11 cities33.7
- 2Chile47 cities27.1
- 3Ghana4 cities24.2
- 4Peru5 cities19.7
- 5India228 cities18.2
- 6Philippines3 cities18.2
- 7Brazil3 cities13.6
- 8Japan559 cities13.6
- 9New Zealand10 cities13.4
- 10Mexico44 cities11.5
- 11Malta5 cities11.3
- 12Spain120 cities11.2
- 13Italy27 cities9.5
- 14Greece10 cities9.4
- 15South Korea140 cities9.3
- 16Bosnia and Herzegovina4 cities8.8
- 17Hungary10 cities8.1
- 18Hong Kong13 cities7.6
- 19Switzerland10 cities7.4
- 20Slovakia41 cities7.4
+ 24 more countries, 7.3 µg/m³ and below
- 29United States852 cities6.0
Not counted on this day, too few cities measured: Luxembourg since 23 Aug 2025, Martinique since 22 Aug 2025, China since 7 Aug 2025 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.