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 31 Oct 2024: Pakistan 77.1 µg/m³, India 42.2 µg/m³ and China 27.1 µg/m³.
- 1Pakistan4 cities77.1
- 2India5 cities42.2
- 3China3 cities27.1
- 4Serbia23 cities25.9
- 5Hungary4 cities21.4
- 6Chile45 cities20.1
- 7Thailand21 cities20.1
- 8Peru17 cities19.9
- 9Hong Kong13 cities17.3
- 10Poland73 cities16.4
- 11Singapore5 cities15.0
- 12Mexico11 cities, was 312.2
- 13South Korea140 cities11.2
- 14Taiwan43 cities10.9
- 15Bulgaria5 cities9.4
- 16United States804 cities7.2
- 17Norway18 cities7.0
- 18The Netherlands22 cities6.9
- 19Japan547 cities6.6
- 20Australia36 cities6.4
+ 4 more countries, 6.3 µg/m³ and below
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.