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 23 Nov 2025: Pakistan 166.1 µg/m³, India 55.4 µg/m³ and Bosnia and Herzegovina 35.3 µg/m³.
- 1Pakistan11 cities166.1
- 2India218 cities55.4
- 3Bosnia and Herzegovina5 cities35.3
- 4Peru5 cities30.6
- 5North Macedonia13 cities25.5
- 6Ghana4 cities21.8
- 7Mexico47 cities20.3
- 8Chile39 cities18.0
- 9Hong Kong13 cities17.7
- 10Philippines3 cities17.2
- 11Poland64 cities16.9
- 12South Korea141 cities16.8
- 13Romania6 cities14.1
- 14Hungary12 cities13.7
- 15Slovakia40 cities, was 4213.3
- 16Montenegro5 cities12.9
- 17Kosovo8 cities12.8
- 18Bulgaria7 cities12.6
- 19Slovenia12 cities12.0
- 20Latvia4 cities10.6
+ 22 more countries, 9.9 µg/m³ and below
- 32United States792 cities6.4
Not counted on this day, too few cities measured: Czechia since 23 Nov 2025, Lithuania since 31 Oct 2025, Brazil since 23 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.