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 24 Dec 2023: Pakistan 123.3 µg/m³, India 107.9 µg/m³ and China 42.4 µg/m³.
- 1Pakistan4 cities123.3
- 2India4 cities107.9
- 3China3 cities42.4
- 4North Macedonia7 cities41.3
- 5Serbia3 cities32.0
- 6Thailand9 cities31.0
- 7Bulgaria5 cities20.4
- 8Hong Kong13 cities20.4
- 9Slovakia27 cities19.6
- 10Mexico44 cities, was 1119.5
- 11Czechia33 cities19.0
- 12Romania8 cities18.8
- 13Chile40 cities17.5
- 14Hungary7 cities17.1
- 15Italy23 cities16.6
- 16Greece9 cities16.0
- 17Lithuania3 cities13.4
- 18Austria29 cities13.3
- 19Belgium41 cities10.3
- 20France134 cities9.8
+ 16 more countries, 9.5 µg/m³ and below
- 25United States758 cities7.8
Not counted on this day, too few cities measured: Martinique since 8 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.