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 13 Oct 2025: Pakistan 62.1 µg/m³, India 38.7 µg/m³ and Peru 27.7 µg/m³.
- 1Pakistan11 cities62.1
- 2India230 cities38.7
- 3Peru5 cities27.7
- 4Chile46 cities19.2
- 5Bosnia and Herzegovina5 cities17.7
- 6North Macedonia13 cities15.4
- 7Switzerland10 cities11.7
- 8Belgium49 cities11.4
- 9Hungary5 cities11.4
- 10Poland60 cities11.0
- 11France101 cities, was 1410.2
- 12Mexico47 cities9.8
- 13Hong Kong13 cities9.7
- 14Martinique3 cities9.0
- 15Slovenia12 cities8.8
- 16Lithuania3 cities8.7
- 17Kosovo7 cities8.7
- 18Australia22 cities8.4
- 19United Kingdom69 cities8.1
- 20Romania11 cities7.7
+ 18 more countries, 7.6 µg/m³ and below
- 34United States855 cities4.8
Not counted on this day, too few cities measured: Thailand since 13 Oct 2025, Taiwan since 13 Oct 2025, Norway since 12 Oct 2025 and 10 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.