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 18 Nov 2024: Pakistan 109.2 µg/m³, India 71.8 µg/m³ and Bosnia and Herzegovina 48.4 µg/m³.
- 1Pakistan4 cities109.2
- 2India5 cities71.8
- 3Bosnia and Herzegovina3 cities48.4
- 4Serbia25 cities42.3
- 5Romania10 cities27.2
- 6Thailand16 cities25.0
- 7China3 cities23.9
- 8Hungary10 cities23.3
- 9Poland75 cities23.2
- 10Slovakia41 cities21.2
- 11Chile46 cities18.8
- 12Czechia22 cities18.8
- 13Hong Kong13 cities18.2
- 14Peru17 cities17.5
- 15Mexico13 cities, was 316.4
- 16Singapore5 cities15.7
- 17Bulgaria8 cities15.4
- 18South Korea141 cities13.2
- 19United Kingdom5 cities, was 6312.8
- 20Belgium45 cities12.5
+ 21 more countries, 11.4 µg/m³ and below
- 34United States822 cities6.8
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.