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 15 Mar 2025: India 44.1 µg/m³, Lithuania 41.7 µg/m³ and Poland 29.5 µg/m³.
- 1India227 cities, was 544.1
- 2Lithuania4 cities41.7
- 3Poland72 cities29.5
- 4Serbia39 cities, was 1225.6
- 5Romania10 cities25.5
- 6Thailand82 cities24.8
- 7South Korea140 cities22.9
- 8Latvia4 cities21.5
- 9Taiwan43 cities20.0
- 10Chile46 cities19.9
- 11Germany249 cities19.9
- 12Mexico47 cities, was 1419.8
- 13Greece9 cities19.4
- 14Peru6 cities19.4
- 15Belgium44 cities19.0
- 16United Kingdom6 cities18.9
- 17Bosnia and Herzegovina4 cities18.6
- 18Hungary12 cities16.3
- 19Hong Kong13 cities14.8
- 20Ireland6 cities14.7
+ 21 more countries, 14.5 µg/m³ and below
- 32United States826 cities7.0
Not counted on this day, too few cities measured: Luxembourg since 15 Mar 2025, Croatia since 14 Mar 2025, Malta since 14 Mar 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.