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 22 Oct 2024: Pakistan 97.6 µg/m³, Bosnia and Herzegovina 39.6 µg/m³ and India 30.7 µg/m³.
- 1Pakistan4 cities97.6
- 2Bosnia and Herzegovina3 cities39.6
- 3India5 cities30.7
- 4China3 cities25.9
- 5Serbia21 cities20.4
- 6Chile45 cities19.0
- 7Peru13 cities18.1
- 8Thailand16 cities17.1
- 9Poland73 cities16.5
- 10Singapore6 cities15.4
- 11Hungary10 cities14.8
- 12Hong Kong13 cities14.5
- 13Romania8 cities13.1
- 14Taiwan42 cities12.4
- 15Brazil33 cities12.1
- 16Slovakia33 cities11.8
- 17Latvia4 cities10.6
- 18Mexico11 cities, was 310.2
- 19South Korea139 cities9.7
- 20Lithuania4 cities9.7
+ 21 more countries, the next at 9.5 µg/m³
- 30United States802 cities6.8
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, Turkey and Iran, which publish only on their own websites. We are building the reader for China's network. The networks of Turkey and Iran don't answer requests from outside their countries, so we can't read them. Most cities there are missing from this board, not clean. Why.