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 3 Jul 2024: Chile 37.0 µg/m³, China 23.1 µg/m³ and India 22.3 µg/m³.
- 1Chile43 cities37.0
- 2China4 cities23.1
- 3India4 cities22.3
- 4Peru13 cities19.6
- 5South Korea141 cities15.3
- 6New Zealand5 cities15.1
- 7Serbia24 cities13.0
- 8Malta5 cities12.3
- 9Greece7 cities11.5
- 10North Macedonia7 cities11.5
- 11Mexico3 cities, was 1011.3
- 12Thailand68 cities11.3
- 13Singapore5 cities11.1
- 14Bosnia and Herzegovina5 cities10.4
- 15Italy5 cities, was 3910.1
- 16Slovakia40 cities10.1
- 17Hungary10 cities10.0
- 18Slovenia12 cities9.4
- 19Poland72 cities9.2
- 20Japan556 cities8.8
+ 21 more countries, 8.1 µg/m³ and below
- 32United States806 cities6.8
Not counted on this day, too few cities measured: Iceland since 27 Jun 2024, Switzerland since 13 Jun 2024, Czechia since 11 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.