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 30 days to 24 May 2024: Chile 40.9 µg/m³, Pakistan 36.9 µg/m³ and Laos 35.6 µg/m³.
- 1Chile45 cities40.9
- 2Pakistan4 cities36.9
- 3Laos3 cities35.6
- 4India5 cities35.5
- 5China3 cities25.2
- 6Thailand82 cities, was 1523.6
- 7Mexico9 cities23.4
- 8Peru12 cities23.4
- 9South Korea141 cities15.4
- 10Malta5 cities15.1
- 11Taiwan43 cities14.6
- 12Hong Kong11 cities12.7
- 13New Zealand5 cities11.9
- 14Belgium44 cities11.6
- 15Serbia24 cities11.2
- 16The Netherlands36 cities10.7
- 17Poland77 cities10.7
- 18Greece7 cities10.3
- 19Latvia4 cities10.0
- 20Singapore5 cities9.9
+ 27 more countries, 9.3 µg/m³ and below
- 37United States810 cities6.3
Not counted on this day, too few cities measured: Bosnia and Herzegovina since 2 May 2024 and Montenegro since 26 Mar 2024.
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.