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 5 Dec 2025: Pakistan 216.2 µg/m³, India 62.0 µg/m³ and Thailand 31.8 µg/m³.
- 1Pakistan13 cities216.2
- 2India238 cities62.0
- 3Thailand74 cities31.8
- 4Laos3 cities28.7
- 5Hong Kong13 cities26.9
- 6Ghana4 cities25.3
- 7Peru5 cities25.3
- 8Philippines3 cities23.5
- 9Slovenia3 cities, was 1222.3
- 10Mexico49 cities21.8
- 11Hungary6 cities21.5
- 12Bulgaria4 cities16.5
- 13Chile40 cities15.8
- 14Taiwan45 cities14.4
- 15Austria9 cities, was 3714.3
- 16South Korea132 cities13.5
- 17Switzerland6 cities, was 1010.9
- 18Germany71 cities, was 24610.8
- 19Japan545 cities8.9
- 20United States864 cities, was 8697.3
+ 8 more countries, 7.1 µg/m³ and below
Not counted on this day, too few cities measured: Serbia since 4 Dec 2025, Senegal since 4 Dec 2025, Bosnia and Herzegovina since 30 Nov 2025 and 22 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.