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 8 Dec 2025: Pakistan 232.7 µg/m³, India 61.8 µg/m³ and Bosnia and Herzegovina 41.6 µg/m³.
- 1Pakistan13 cities232.7
- 2India250 cities61.8
- 3Bosnia and Herzegovina5 cities41.6
- 4North Macedonia13 cities39.1
- 5Hong Kong13 cities31.2
- 6Thailand71 cities26.9
- 7Ghana4 cities26.1
- 8Montenegro5 cities24.4
- 9Poland67 cities24.1
- 10Laos3 cities23.9
- 11Peru5 cities22.3
- 12Mexico54 cities21.3
- 13Slovenia12 cities, was 1220.8
- 14Philippines3 cities19.8
- 15Hungary13 cities19.1
- 16Chile44 cities17.1
- 17South Korea141 cities16.2
- 18Slovakia11 cities, was 3316.2
- 19Czechia24 cities, was 2315.0
- 20Latvia4 cities14.2
+ 26 more countries, 14.0 µg/m³ and below
- 29United States865 cities, was 8698.3
Not counted on this day, too few cities measured: Serbia since 4 Dec 2025, Senegal since 4 Dec 2025, Kosovo since 27 Nov 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.