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 Oct 2023: Pakistan 54.9 µg/m³, India 45.5 µg/m³ and Peru 28.0 µg/m³.
- 1Pakistan4 cities54.9
- 2India4 cities45.5
- 3Peru4 cities28.0
- 4China3 cities26.0
- 5Chile44 cities21.4
- 6Singapore5 cities19.9
- 7Thailand10 cities17.6
- 8Serbia3 cities15.5
- 9Malta4 cities15.2
- 10Greece6 cities14.7
- 11Mexico36 cities13.8
- 12North Macedonia7 cities13.5
- 13Italy31 cities, was 412.6
- 14Hong Kong12 cities12.2
- 15Hungary10 cities11.5
- 16Czechia36 cities10.8
- 17Slovakia27 cities9.9
- 18Romania7 cities9.8
- 19Bulgaria6 cities9.6
- 20Spain77 cities9.1
+ 15 more countries, 8.3 µg/m³ and below
- 29United States774 cities6.9
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.