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 5 Nov 2025: Pakistan 163.0 µg/m³, India 37.0 µg/m³ and Peru 29.8 µg/m³.
- 1Pakistan11 cities163.0
- 2India211 cities37.0
- 3Peru6 cities29.8
- 4North Macedonia13 cities26.6
- 5Bosnia and Herzegovina5 cities25.1
- 6Chile39 cities18.6
- 7Romania10 cities18.2
- 8Mexico51 cities18.0
- 9Hong Kong13 cities17.9
- 10Poland67 cities17.2
- 11South Korea141 cities16.0
- 12Bulgaria7 cities13.9
- 13Czechia32 cities12.5
- 14Slovakia32 cities12.1
- 15Kosovo8 cities12.0
- 16Montenegro5 cities10.7
- 17Hungary11 cities10.4
- 18Latvia4 cities9.6
- 19Greece9 cities9.5
- 20Austria35 cities8.2
+ 22 more countries, 7.8 µg/m³ and below
- 27United States854 cities6.2
Not counted on this day, too few cities measured: Ghana since 2 Nov 2025, Philippines since 2 Nov 2025, Lithuania since 29 Oct 2025 and 6 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.