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 25 Nov 2025: Pakistan 215.8 µg/m³, India 68.5 µg/m³ and Bosnia and Herzegovina 33.5 µg/m³.
- 1Pakistan12 cities215.8
- 2India241 cities68.5
- 3Bosnia and Herzegovina5 cities33.5
- 4Ghana3 cities25.4
- 5South Korea135 cities24.7
- 6Peru4 cities24.1
- 7Mexico47 cities23.6
- 8Serbia38 cities22.8
- 9Poland63 cities22.0
- 10Hong Kong13 cities20.2
- 11North Macedonia12 cities19.1
- 12Thailand74 cities18.2
- 13Chile43 cities17.7
- 14Taiwan45 cities16.2
- 15Hungary13 cities13.4
- 16Kosovo7 cities13.2
- 17Slovakia41 cities12.7
- 18Latvia4 cities12.3
- 19Montenegro5 cities11.0
- 20Slovenia12 cities10.9
+ 23 more countries, 10.4 µg/m³ and below
- 28United States804 cities, was 8698.5
Not counted on this day, too few cities measured: Luxembourg since 24 Nov 2025, Czechia since 23 Nov 2025, Martinique since 21 Nov 2025 and 5 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.