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 Dec 2025: Pakistan 190.4 µg/m³, India 62.2 µg/m³ and North Macedonia 61.3 µg/m³.
- 1Pakistan13 cities190.4
- 2India240 cities62.2
- 3North Macedonia12 cities61.3
- 4Montenegro5 cities56.6
- 5Bosnia and Herzegovina5 cities46.8
- 6Ghana3 cities34.3
- 7Peru6 cities30.0
- 8Thailand78 cities25.4
- 9Poland62 cities25.0
- 10Romania25 cities24.6
- 11Bulgaria7 cities22.2
- 12Hong Kong13 cities20.6
- 13Laos3 cities20.2
- 14Mexico52 cities20.2
- 15Hungary12 cities20.0
- 16South Korea140 cities17.8
- 17Chile42 cities17.1
- 18Greece9 cities16.0
- 19Taiwan44 cities15.5
- 20Slovakia18 cities, was 3315.1
+ 26 more countries, 12.3 µg/m³ and below
- 36United States865 cities7.0
Not counted on this day, too few cities measured: Philippines since 19 Dec 2025, Malta since 16 Dec 2025, Sweden since 14 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.