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 26 Oct 2023: Pakistan 74.9 µg/m³, India 67.2 µg/m³ and China 39.6 µg/m³.
- 1Pakistan3 cities74.9
- 2India4 cities67.2
- 3China3 cities39.6
- 4Thailand10 cities24.8
- 5Chile15 cities20.9
- 6Greece9 cities17.0
- 7Malta4 cities16.3
- 8North Macedonia7 cities15.6
- 9Singapore5 cities14.6
- 10Mexico11 cities, was 4213.1
- 11Romania6 cities12.5
- 12Czechia34 cities12.4
- 13Serbia3 cities12.0
- 14Hungary6 cities10.8
- 15Slovakia25 cities9.0
- 16Bulgaria6 cities8.8
- 17Austria30 cities8.6
- 18Japan523 cities8.3
- 19Italy23 cities8.1
- 20United Kingdom6 cities, was 616.6
+ 15 more countries, 6.6 µg/m³ and below
- 21United States743 cities6.6
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.