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 7 Dec 2025: Pakistan 222.4 µg/m³, India 61.4 µg/m³ and Bosnia and Herzegovina 43.0 µg/m³.
- 1Pakistan13 cities222.4
- 2India248 cities61.4
- 3Bosnia and Herzegovina5 cities43.0
- 4North Macedonia13 cities41.7
- 5Montenegro4 cities33.4
- 6Hong Kong13 cities29.4
- 7Thailand71 cities28.7
- 8Poland64 cities25.4
- 9Ghana4 cities25.1
- 10Laos3 cities24.0
- 11Mexico52 cities23.2
- 12Peru5 cities23.1
- 13Slovenia12 cities, was 1221.2
- 14Philippines3 cities21.1
- 15Slovakia7 cities, was 3319.4
- 16Hungary12 cities18.1
- 17Chile44 cities16.5
- 18South Korea141 cities16.5
- 19Bulgaria4 cities15.5
- 20Austria39 cities, was 3713.8
+ 24 more countries, 13.6 µg/m³ and below
- 28United States869 cities, was 8698.4
Not counted on this day, too few cities measured: Serbia since 4 Dec 2025, Senegal since 4 Dec 2025, Malta since 30 Nov 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.