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 17 Mar 2025: India 40.6 µg/m³, Lithuania 26.4 µg/m³ and Thailand 23.6 µg/m³.
- 1India220 cities, was 540.6
- 2Lithuania4 cities26.4
- 3Thailand85 cities23.6
- 4Poland72 cities22.0
- 5Chile46 cities20.4
- 6Mexico54 cities, was 1420.4
- 7Serbia39 cities, was 1220.2
- 8Taiwan43 cities20.2
- 9Greece8 cities19.8
- 10South Korea141 cities19.2
- 11Peru6 cities18.7
- 12Romania10 cities18.3
- 13Hong Kong13 cities14.9
- 14Latvia4 cities14.3
- 15Bosnia and Herzegovina4 cities14.2
- 16Germany236 cities13.4
- 17Belgium44 cities12.2
- 18France106 cities, was 2312.1
- 19Bulgaria8 cities10.1
- 20Hungary8 cities9.7
+ 21 more countries, 9.1 µg/m³ and below
- 29United States825 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.