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 16 Mar 2025: India 41.5 µg/m³, Lithuania 32.6 µg/m³ and Poland 26.4 µg/m³.
- 1India222 cities, was 541.5
- 2Lithuania4 cities32.6
- 3Poland72 cities26.4
- 4Thailand82 cities24.7
- 5Serbia39 cities, was 1223.3
- 6Romania10 cities22.4
- 7South Korea141 cities21.0
- 8Greece9 cities20.2
- 9Mexico52 cities, was 1420.1
- 10Chile46 cities20.0
- 11Taiwan43 cities19.9
- 12Peru6 cities18.7
- 13Latvia4 cities17.4
- 14Germany236 cities17.1
- 15Belgium44 cities16.5
- 16United Kingdom6 cities15.4
- 17Bosnia and Herzegovina4 cities14.4
- 18Hong Kong13 cities13.4
- 19Hungary9 cities12.9
- 20The Netherlands29 cities11.5
+ 21 more countries, 11.0 µg/m³ and below
- 30United States826 cities7.1
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.