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 16 May 2024: Chile 52.9 µg/m³, Pakistan 40.3 µg/m³ and China 28.5 µg/m³.
- 1Chile44 cities52.9
- 2Pakistan4 cities40.3
- 3China3 cities28.5
- 4India5 cities28.1
- 5Mexico12 cities27.2
- 6Peru11 cities25.1
- 7Laos3 cities23.7
- 8Thailand76 cities, was 1320.3
- 9New Zealand5 cities18.0
- 10Malta5 cities15.3
- 11Taiwan43 cities14.8
- 12Hong Kong13 cities14.4
- 13Puerto Rico3 cities13.2
- 14South Korea141 cities12.4
- 15The Netherlands36 cities12.0
- 16Ireland6 cities11.4
- 17United Kingdom63 cities, was 1111.2
- 18Singapore5 cities11.2
- 19Belgium44 cities11.0
- 20Italy35 cities10.3
+ 29 more countries, 10.3 µg/m³ and below
- 40United States784 cities5.9
Not counted on this day, too few cities measured: Austria since 10 May 2024, Bosnia and Herzegovina since 26 Apr 2024 and Montenegro since 22 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.