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 Oct 2023: Pakistan 56.3 µg/m³, India 51.2 µg/m³ and Peru 28.0 µg/m³.
- 1Pakistan4 cities56.3
- 2India4 cities51.2
- 3Peru4 cities28.0
- 4China3 cities25.8
- 5Chile44 cities21.1
- 6Singapore5 cities20.7
- 7Thailand10 cities19.1
- 8Serbia3 cities16.2
- 9Malta4 cities15.4
- 10Greece6 cities14.4
- 11Mexico27 cities14.4
- 12North Macedonia7 cities13.0
- 13Italy30 cities, was 412.8
- 14Hong Kong10 cities12.7
- 15Czechia36 cities11.9
- 16Hungary10 cities11.6
- 17Romania7 cities10.5
- 18Slovakia27 cities10.4
- 19Bulgaria6 cities9.8
- 20Austria30 cities9.3
+ 15 more countries, 9.0 µg/m³ and below
- 30United States775 cities6.7
Not counted on this day, too few cities measured: Poland since 8 Oct 2023.
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.