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 30 days to 11 Aug 2025: Chile 40.7 µg/m³, Pakistan 35.0 µg/m³ and Peru 29.3 µg/m³.
- 1Chile47 cities40.7
- 2Pakistan11 cities35.0
- 3Peru5 cities29.3
- 4Ghana3 cities25.6
- 5India216 cities21.4
- 6Philippines3 cities20.4
- 7New Zealand10 cities16.2
- 8Mexico45 cities12.5
- 9Canada115 cities12.0
- 10South Korea140 cities11.5
- 11Hong Kong13 cities11.2
- 12Greece8 cities10.3
- 13Italy27 cities, was 710.3
- 14Malta4 cities10.2
- 15Romania11 cities9.9
- 16Martinique3 cities9.5
- 17Spain99 cities9.1
- 18Finland15 cities, was 39.0
- 19Slovakia41 cities9.0
- 20Bosnia and Herzegovina5 cities8.6
+ 25 more countries, 8.6 µg/m³ and below
- 24United States853 cities8.5
Not counted on this day, too few cities measured: Serbia since 10 Jul 2025, Thailand since 10 Jul 2025 and Taiwan since 10 Jul 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.