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 26 Jun 2024: Chile 37.3 µg/m³, India 24.8 µg/m³ and China 22.1 µg/m³.
- 1Chile44 cities37.3
- 2India4 cities24.8
- 3China3 cities22.1
- 4Peru13 cities19.5
- 5Mexico5 cities17.4
- 6South Korea141 cities15.4
- 7New Zealand5 cities15.3
- 8Serbia24 cities12.3
- 9North Macedonia8 cities11.8
- 10Malta5 cities11.7
- 11Greece6 cities11.3
- 12Thailand69 cities11.3
- 13Bosnia and Herzegovina5 cities11.2
- 14Singapore5 cities10.8
- 15Poland72 cities9.6
- 16Slovakia41 cities9.6
- 17Italy5 cities, was 399.4
- 18Hungary10 cities9.2
- 19Japan554 cities8.5
- 20Latvia4 cities8.5
+ 21 more countries, 8.4 µg/m³ and below
- 30United States804 cities6.8
Not counted on this day, too few cities measured: Luxembourg since 26 Jun 2024, Switzerland since 13 Jun 2024, Czechia since 11 Jun 2024 and 5 more countries.
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.