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 22 Jun 2024: Chile 38.6 µg/m³, Peru 25.7 µg/m³ and India 24.9 µg/m³.
- 1Chile44 cities38.6
- 2Peru11 cities25.7
- 3India4 cities24.9
- 4China3 cities22.0
- 5Mexico6 cities21.6
- 6New Zealand5 cities15.8
- 7South Korea141 cities15.6
- 8Serbia24 cities12.0
- 9Greece6 cities11.4
- 10Thailand71 cities11.3
- 11Malta5 cities11.1
- 12North Macedonia8 cities10.9
- 13Singapore5 cities10.5
- 14Poland72 cities10.1
- 15Slovakia40 cities9.3
- 16Hungary10 cities9.1
- 17Taiwan43 cities9.1
- 18Italy6 cities, was 398.9
- 19Latvia4 cities8.9
- 20Japan556 cities8.6
+ 21 more countries, 8.5 µg/m³ and below
- 30United States808 cities6.8
Not counted on this day, too few cities measured: Switzerland since 13 Jun 2024, Czechia since 11 Jun 2024, Pakistan since 9 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.