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 27 Oct 2023: Pakistan 83.2 µg/m³, India 66.9 µg/m³ and China 46.0 µg/m³.
- 1Pakistan3 cities83.2
- 2India4 cities66.9
- 3China3 cities46.0
- 4Thailand9 cities22.9
- 5Chile15 cities20.2
- 6Greece9 cities18.2
- 7North Macedonia7 cities16.1
- 8Malta4 cities16.1
- 9Singapore5 cities14.4
- 10Mexico11 cities, was 4213.0
- 11Romania6 cities11.9
- 12Serbia3 cities10.7
- 13Czechia33 cities9.7
- 14Hungary6 cities9.3
- 15Japan524 cities8.5
- 16Bulgaria6 cities8.0
- 17Italy24 cities7.2
- 18Slovakia25 cities7.0
- 19Austria30 cities6.8
- 20United States742 cities6.8
+ 15 more countries, 6.5 µg/m³ and below
Not counted on this day, too few cities measured: Hong Kong since 17 Oct 2023, Peru since 17 Oct 2023, Poland since 1 Oct 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.