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 21 Feb 2025: India 79.9 µg/m³, Pakistan 74.8 µg/m³ and Bosnia and Herzegovina 51.7 µg/m³.
- 1India5 cities79.9
- 2Pakistan4 cities74.8
- 3Bosnia and Herzegovina4 cities51.7
- 4Thailand84 cities, was 1641.6
- 5Serbia25 cities41.2
- 6China4 cities32.7
- 7Poland76 cities28.6
- 8Laos3 cities28.2
- 9Slovenia12 cities27.7
- 10Romania8 cities26.9
- 11Czechia27 cities, was 3624.2
- 12Hungary11 cities22.5
- 13Bulgaria5 cities22.3
- 14Slovakia42 cities22.0
- 15Chile45 cities19.7
- 16Croatia3 cities19.3
- 17Hong Kong13 cities18.8
- 18Austria36 cities18.7
- 19Belgium45 cities18.4
- 20The Netherlands24 cities18.4
+ 26 more countries, 18.0 µg/m³ and below
- 38United States823 cities7.1
Not counted on this day, too few cities measured: Luxembourg since 2 Feb 2025 and Singapore since 16 Jan 2025.
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.