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 30 days to 25 Dec 2025: Pakistan 224.1 µg/m³, India 62.7 µg/m³ and Bosnia and Herzegovina 61.9 µg/m³.
- 1Pakistan13 cities224.1
- 2India240 cities62.7
- 3Bosnia and Herzegovina5 cities61.9
- 4Montenegro4 cities53.5
- 5North Macedonia12 cities51.0
- 6Ghana3 cities32.0
- 7Peru6 cities28.1
- 8Thailand71 cities25.4
- 9Hong Kong13 cities24.7
- 10Poland63 cities22.9
- 11Romania16 cities, was 1121.2
- 12Mexico50 cities20.6
- 13Bulgaria7 cities19.6
- 14Laos3 cities19.3
- 15Slovenia12 cities18.8
- 16Hungary13 cities18.7
- 17South Korea139 cities18.2
- 18Chile42 cities16.8
- 19Philippines3 cities16.8
- 20Taiwan45 cities15.5
+ 22 more countries, 14.0 µg/m³ and below
- 34United States871 cities7.3
Not counted on this day, too few cities measured: Sweden since 17 Dec 2025, Malta since 16 Dec 2025, Ireland since 15 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.