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 24 May 2024: Chile 46.3 µg/m³, Pakistan 36.5 µg/m³ and Mexico 26.0 µg/m³.
- 1Chile44 cities46.3
- 2Pakistan4 cities36.5
- 3Mexico10 cities26.0
- 4Malta5 cities25.7
- 5India3 cities23.8
- 6Peru11 cities20.6
- 7China3 cities19.5
- 8Laos3 cities18.7
- 9South Korea141 cities18.2
- 10Greece8 cities15.8
- 11Taiwan43 cities15.3
- 12Belgium44 cities15.1
- 13Thailand76 cities13.1
- 14North Macedonia9 cities12.4
- 15New Zealand5 cities12.0
- 16The Netherlands36 cities11.7
- 17Japan557 cities11.5
- 18Poland76 cities11.0
- 19Serbia24 cities10.8
- 20Hong Kong3 cities, was 1110.3
+ 27 more countries, 10.2 µg/m³ and below
- 37United States787 cities6.7
Not counted on this day, too few cities measured: Puerto Rico since 23 May 2024, Luxembourg since 19 May 2024, Austria since 10 May 2024 and Bosnia and Herzegovina since 26 Apr 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.