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 13 Mar 2025: India 45.2 µg/m³, Serbia 43.0 µg/m³ and Bosnia and Herzegovina 38.6 µg/m³.
- 1India172 cities, was 545.2
- 2Serbia39 cities43.0
- 3Bosnia and Herzegovina4 cities38.6
- 4Poland74 cities35.0
- 5Romania8 cities33.9
- 6China3 cities33.8
- 7Thailand86 cities, was 1629.6
- 8Bulgaria8 cities27.2
- 9Slovenia12 cities26.1
- 10Hungary12 cities24.5
- 11Slovakia34 cities24.1
- 12Laos3 cities23.8
- 13Latvia4 cities22.4
- 14Belgium41 cities20.5
- 15Hong Kong13 cities19.6
- 16Germany223 cities19.3
- 17South Korea141 cities19.1
- 18Austria36 cities19.0
- 19United Kingdom5 cities18.7
- 20Chile44 cities18.5
+ 15 more countries, 17.8 µg/m³ and below
- 31United States830 cities6.6
Not counted on this day, too few cities measured: Malta since 13 Mar 2025, Pakistan since 13 Mar 2025, Switzerland since 12 Mar 2025 and 10 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.