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 4 Nov 2025: Pakistan 158.5 µg/m³, India 35.4 µg/m³ and Peru 30.5 µg/m³.
- 1Pakistan11 cities158.5
- 2India211 cities35.4
- 3Peru6 cities30.5
- 4North Macedonia13 cities27.8
- 5Bosnia and Herzegovina5 cities23.3
- 6Hong Kong13 cities18.9
- 7Chile39 cities18.8
- 8Mexico50 cities17.9
- 9Romania10 cities17.9
- 10Poland64 cities15.8
- 11South Korea141 cities14.8
- 12Bulgaria7 cities14.3
- 13Czechia32 cities12.3
- 14Kosovo8 cities11.9
- 15Montenegro5 cities10.5
- 16Latvia4 cities9.4
- 17Greece9 cities9.3
- 18Hungary11 cities9.2
- 19Malta4 cities7.5
- 20Japan547 cities7.4
+ 21 more countries, 7.2 µg/m³ and below
- 26United States858 cities5.8
Not counted on this day, too few cities measured: Ghana since 2 Nov 2025, Philippines since 2 Nov 2025, Slovakia since 31 Oct 2025 and 7 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.