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 20 Jun 2024: Chile 41.3 µg/m³, Peru 25.4 µg/m³ and India 24.8 µg/m³.
- 1Chile45 cities41.3
- 2Peru11 cities25.4
- 3India4 cities24.8
- 4Mexico10 cities22.3
- 5China3 cities21.6
- 6South Korea141 cities16.2
- 7New Zealand5 cities16.0
- 8Serbia24 cities11.5
- 9Greece6 cities11.4
- 10Thailand71 cities11.2
- 11Singapore5 cities10.7
- 12Malta5 cities10.6
- 13North Macedonia8 cities10.2
- 14Poland72 cities10.1
- 15Taiwan43 cities9.5
- 16Italy13 cities9.4
- 17Slovakia40 cities9.1
- 18Latvia4 cities9.0
- 19Japan557 cities8.7
- 20Lithuania4 cities8.7
+ 21 more countries, 8.5 µg/m³ and below
- 30United States806 cities6.7
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.