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 9 Dec 2025: Pakistan 227.1 µg/m³, India 60.2 µg/m³ and Bosnia and Herzegovina 40.0 µg/m³.
- 1Pakistan13 cities227.1
- 2India249 cities60.2
- 3Bosnia and Herzegovina5 cities40.0
- 4North Macedonia13 cities33.2
- 5Hong Kong13 cities32.7
- 6Ghana4 cities27.5
- 7Thailand71 cities25.7
- 8Montenegro5 cities25.3
- 9Peru6 cities24.5
- 10Poland67 cities23.9
- 11Laos3 cities22.3
- 12Hungary13 cities21.1
- 13Mexico53 cities20.7
- 14Slovenia12 cities, was 1220.2
- 15Slovakia14 cities, was 3317.9
- 16Philippines3 cities17.2
- 17Chile44 cities17.0
- 18South Korea141 cities16.2
- 19Czechia24 cities, was 2314.3
- 20Bulgaria7 cities14.0
+ 27 more countries, 13.8 µg/m³ and below
- 28United States866 cities, was 8698.2
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.