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 18 Dec 2023: Pakistan 154.1 µg/m³, India 80.3 µg/m³ and North Macedonia 42.2 µg/m³.
- 1Pakistan4 cities154.1
- 2India5 cities80.3
- 3North Macedonia7 cities42.2
- 4China3 cities40.9
- 5Serbia3 cities38.1
- 6Thailand9 cities36.0
- 7Slovakia27 cities22.4
- 8Bulgaria5 cities20.5
- 9Hungary7 cities19.4
- 10Romania8 cities18.4
- 11Chile44 cities17.1
- 12Mexico44 cities, was 1116.7
- 13Hong Kong13 cities16.3
- 14Italy24 cities, was 2815.6
- 15Czechia34 cities15.5
- 16Greece9 cities15.3
- 17Austria29 cities11.4
- 18France131 cities10.7
- 19Belgium41 cities10.5
- 20Lithuania3 cities10.5
+ 16 more countries, 9.5 µg/m³ and below
- 26United States764 cities7.6
Not counted on this day, too few cities measured: Luxembourg since 5 Dec 2023 and Martinique since 1 Dec 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.