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 14 Mar 2025: India 45.4 µg/m³, Lithuania 45.0 µg/m³ and Poland 33.8 µg/m³.
- 1India220 cities, was 545.4
- 2Lithuania4 cities45.0
- 3Poland73 cities33.8
- 4Serbia39 cities, was 1228.5
- 5Latvia4 cities25.9
- 6South Korea140 cities25.0
- 7Romania10 cities25.0
- 8Thailand82 cities24.7
- 9Bosnia and Herzegovina4 cities22.9
- 10Germany250 cities21.4
- 11United Kingdom6 cities21.0
- 12Belgium44 cities20.5
- 13Taiwan43 cities20.2
- 14Mexico25 cities19.9
- 15Peru6 cities19.7
- 16Chile46 cities19.1
- 17Hungary12 cities18.1
- 18Slovakia42 cities17.5
- 19Greece8 cities17.4
- 20Hong Kong13 cities16.6
+ 22 more countries, 16.6 µg/m³ and below
- 34United States824 cities6.5
Not counted on this day, too few cities measured: Croatia since 14 Mar 2025, Malta since 14 Mar 2025, China since 7 Mar 2025 and 3 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.