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 17 Jun 2024: Chile 43.6 µg/m³, Peru 24.5 µg/m³ and India 24.4 µg/m³.
- 1Chile45 cities43.6
- 2Peru11 cities24.5
- 3India4 cities24.4
- 4Mexico12 cities22.7
- 5China3 cities21.7
- 6South Korea141 cities15.8
- 7New Zealand5 cities15.7
- 8Greece7 cities13.4
- 9Malta5 cities12.9
- 10Thailand71 cities11.8
- 11Serbia24 cities11.0
- 12Italy15 cities10.9
- 13Poland72 cities10.5
- 14North Macedonia8 cities10.3
- 15Taiwan43 cities10.2
- 16Singapore5 cities10.0
- 17Latvia4 cities9.5
- 18Lithuania4 cities9.1
- 19Hong Kong10 cities9.0
- 20Japan557 cities8.9
+ 21 more countries, 8.7 µg/m³ and below
- 33United States803 cities6.5
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.