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 23 May 2024: Chile 40.2 µg/m³, Laos 37.0 µg/m³ and Pakistan 36.8 µg/m³.
- 1Chile45 cities40.2
- 2Laos3 cities37.0
- 3Pakistan4 cities36.8
- 4India5 cities36.2
- 5China3 cities25.4
- 6Thailand83 cities, was 1524.5
- 7Peru12 cities23.5
- 8Mexico9 cities23.3
- 9Malta5 cities15.4
- 10South Korea141 cities15.1
- 11Taiwan43 cities14.6
- 12Hong Kong12 cities13.1
- 13Greece7 cities12.9
- 14New Zealand5 cities11.8
- 15Belgium44 cities11.4
- 16Serbia24 cities11.4
- 17Poland77 cities10.9
- 18The Netherlands36 cities10.6
- 19Singapore5 cities10.0
- 20Latvia4 cities9.9
+ 27 more countries, 9.4 µg/m³ and below
- 38United States810 cities6.2
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.