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 21 Oct 2024: Pakistan 91.8 µg/m³, Bosnia and Herzegovina 39.6 µg/m³ and India 29.6 µg/m³.
- 1Pakistan4 cities91.8
- 2Bosnia and Herzegovina3 cities39.6
- 3India5 cities29.6
- 4China3 cities27.3
- 5Peru14 cities19.9
- 6Chile45 cities19.4
- 7Thailand16 cities17.4
- 8Serbia21 cities16.8
- 9Poland73 cities15.8
- 10Hungary10 cities14.6
- 11Hong Kong13 cities14.4
- 12Singapore5 cities14.3
- 13Romania8 cities13.1
- 14Taiwan42 cities12.9
- 15Slovakia33 cities11.8
- 16Mexico11 cities, was 310.8
- 17Latvia4 cities10.6
- 18South Korea139 cities10.4
- 19Lithuania4 cities9.7
- 20Sweden4 cities9.5
+ 20 more countries, 9.3 µg/m³ and below
- 33United States795 cities6.3
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.