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 10 Dec 2025: Pakistan 220.8 µg/m³, India 59.9 µg/m³ and Bosnia and Herzegovina 37.7 µg/m³.
- 1Pakistan13 cities220.8
- 2India251 cities59.9
- 3Bosnia and Herzegovina5 cities37.7
- 4Montenegro5 cities31.6
- 5Hong Kong13 cities31.4
- 6Ghana3 cities31.0
- 7North Macedonia13 cities29.6
- 8Thailand71 cities24.5
- 9Peru6 cities24.2
- 10Poland68 cities23.7
- 11Hungary13 cities21.5
- 12Mexico55 cities20.5
- 13Laos3 cities19.6
- 14Slovenia12 cities, was 1218.6
- 15South Korea141 cities18.4
- 16Slovakia14 cities, was 3318.0
- 17Chile45 cities16.9
- 18Bulgaria7 cities14.0
- 19Romania17 cities13.9
- 20Czechia24 cities, was 2313.8
+ 26 more countries, 13.2 µg/m³ and below
- 26United States863 cities, was 8698.0
Not counted on this day, too few cities measured: Philippines since 10 Dec 2025, Serbia since 4 Dec 2025, Senegal since 4 Dec 2025 and 4 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.