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 7 Oct 2023: Pakistan 43.9 µg/m³, India 38.2 µg/m³ and Peru 23.9 µg/m³.
- 1Pakistan3 cities43.9
- 2India4 cities38.2
- 3Peru5 cities23.9
- 4Singapore5 cities23.6
- 5Chile43 cities20.7
- 6China3 cities20.4
- 7Malta4 cities16.9
- 8Hong Kong12 cities16.3
- 9Serbia3 cities16.1
- 10Italy30 cities15.6
- 11Greece8 cities15.1
- 12North Macedonia7 cities14.5
- 13Thailand11 cities13.5
- 14Mexico39 cities12.8
- 15Spain78 cities12.4
- 16Bulgaria6 cities11.3
- 17Switzerland8 cities11.2
- 18Romania7 cities9.7
- 19Czechia34 cities9.3
- 20Germany61 cities9.1
+ 15 more countries, 8.9 µg/m³ and below
- 27United States768 cities7.4
Not counted on this day, too few cities measured: Martinique since 7 Oct 2023, Poland since 1 Oct 2023, Lithuania since 11 Sep 2023 and Luxembourg since 6 Sep 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.