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 16 Jul 2025: Chile 53.9 µg/m³, Pakistan 39.0 µg/m³ and Peru 27.5 µg/m³.
- 1Chile47 cities53.9
- 2Pakistan11 cities39.0
- 3Peru5 cities27.5
- 4India210 cities20.8
- 5New Zealand10 cities13.6
- 6Japan567 cities13.3
- 7South Korea140 cities13.0
- 8Mexico34 cities12.5
- 9Italy19 cities, was 2011.7
- 10Martinique3 cities11.6
- 11Bosnia and Herzegovina5 cities10.8
- 12Slovakia41 cities10.5
- 13Spain112 cities, was 879.5
- 14Hungary8 cities, was 129.3
- 15Greece6 cities8.6
- 16Romania11 cities8.4
- 17Slovenia12 cities8.2
- 18United States842 cities8.2
- 19Canada117 cities7.9
- 20Poland59 cities7.6
+ 18 more countries, 7.4 µg/m³ and below
Not counted on this day, too few cities measured: Serbia since 10 Jul 2025, Thailand since 10 Jul 2025, Taiwan since 10 Jul 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.