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 12 Mar 2025: Pakistan 48.9 µg/m³, India 44.6 µg/m³ and Serbia 43.9 µg/m³.
- 1Pakistan3 cities48.9
- 2India148 cities, was 544.6
- 3Serbia39 cities43.9
- 4Bosnia and Herzegovina4 cities41.0
- 5China3 cities36.5
- 6Poland74 cities35.4
- 7Romania8 cities31.8
- 8Thailand86 cities, was 1630.1
- 9Slovenia12 cities28.1
- 10Bulgaria8 cities27.8
- 11Hungary12 cities25.2
- 12Slovakia34 cities25.0
- 13Laos3 cities23.3
- 14Latvia4 cities22.1
- 15Belgium42 cities20.8
- 16Germany225 cities19.9
- 17Austria36 cities19.7
- 18Hong Kong13 cities19.6
- 19United Kingdom5 cities19.4
- 20South Korea141 cities19.3
+ 17 more countries, 19.0 µg/m³ and below
- 33United States831 cities6.6
Not counted on this day, too few cities measured: Switzerland since 12 Mar 2025, Croatia since 12 Mar 2025, Portugal since 10 Mar 2025 and 8 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.