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 Jun 2024: Chile 38.2 µg/m³, India 24.9 µg/m³ and Peru 22.5 µg/m³.
- 1Chile44 cities38.2
- 2India4 cities24.9
- 3Peru12 cities22.5
- 4China3 cities21.8
- 5Mexico5 cities19.0
- 6New Zealand5 cities15.8
- 7South Korea141 cities15.2
- 8Serbia24 cities12.0
- 9Thailand70 cities11.5
- 10Greece6 cities11.3
- 11North Macedonia8 cities11.3
- 12Malta5 cities11.2
- 13Singapore5 cities10.5
- 14Poland72 cities9.9
- 15Slovakia40 cities9.4
- 16Hungary10 cities9.1
- 17Taiwan43 cities8.9
- 18Italy5 cities, was 398.7
- 19Latvia4 cities8.7
- 20Lithuania4 cities8.4
+ 21 more countries, 8.3 µg/m³ and below
- 29United States806 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.