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 19 Oct 2023: India 68.2 µg/m³, Pakistan 43.6 µg/m³ and China 30.5 µg/m³.
- 1India4 cities68.2
- 2Pakistan4 cities43.6
- 3China3 cities30.5
- 4Thailand10 cities25.6
- 5Serbia3 cities22.1
- 6Chile46 cities21.3
- 7Singapore5 cities19.7
- 8North Macedonia7 cities15.0
- 9Malta4 cities14.7
- 10Hungary8 cities13.2
- 11Romania7 cities12.7
- 12Czechia35 cities12.5
- 13Slovakia26 cities12.2
- 14Greece9 cities11.8
- 15Mexico11 cities, was 4211.8
- 16Austria30 cities10.8
- 17Italy30 cities10.7
- 18Bulgaria6 cities9.8
- 19Japan528 cities8.9
- 20Switzerland8 cities8.4
+ 12 more countries, 8.2 µg/m³ and below
- 28United States761 cities5.3
Not counted on this day, too few cities measured: Martinique since 18 Oct 2023, Australia since 17 Oct 2023, Hong Kong since 17 Oct 2023 and 4 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.