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 7 days to 17 Jun 2024: Pakistan 45.5 µg/m³, China 25.7 µg/m³ and Chile 24.1 µg/m³.
- 1Pakistan3 cities45.5
- 2China4 cities25.7
- 3Chile42 cities24.1
- 4India4 cities23.3
- 5Peru13 cities21.5
- 6South Korea140 cities18.1
- 7New Zealand5 cities15.2
- 8Mexico5 cities13.6
- 9Greece7 cities13.4
- 10Singapore5 cities12.4
- 11Serbia18 cities11.7
- 12Thailand68 cities11.7
- 13Malta5 cities11.6
- 14Japan560 cities10.6
- 15North Macedonia8 cities9.2
- 16Poland73 cities8.4
- 17Hong Kong12 cities, was 118.1
- 18Taiwan43 cities8.0
- 19Italy5 cities, was 387.9
- 20Slovakia38 cities7.9
+ 22 more countries, 7.6 µg/m³ and below
- 23United States794 cities7.5
Not counted on this day, too few cities measured: Switzerland since 6 Jun 2024, Iceland since 6 Jun 2024, Czechia since 3 Jun 2024 and 6 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.