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 16 Dec 2023: Pakistan 165.5 µg/m³, India 119.8 µg/m³ and Thailand 42.3 µg/m³.
- 1Pakistan4 cities165.5
- 2India4 cities119.8
- 3Thailand9 cities42.3
- 4North Macedonia7 cities42.2
- 5China3 cities32.8
- 6Serbia3 cities30.7
- 7Slovakia27 cities20.9
- 8Bulgaria5 cities19.7
- 9Greece10 cities19.7
- 10Hungary7 cities18.0
- 11Chile44 cities17.3
- 12Romania8 cities16.9
- 13Lithuania3 cities15.8
- 14Mexico45 cities, was 1115.7
- 15Italy24 cities, was 2815.6
- 16Hong Kong13 cities15.4
- 17Czechia34 cities14.8
- 18Austria29 cities11.9
- 19Australia23 cities, was 39.8
- 20Belgium41 cities9.0
+ 16 more countries, 8.2 µg/m³ and below
- 27United States752 cities7.3
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.