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 20 Dec 2023: Pakistan 139.0 µg/m³, India 92.1 µg/m³ and Serbia 56.6 µg/m³.
- 1Pakistan4 cities139.0
- 2India5 cities92.1
- 3Serbia3 cities56.6
- 4North Macedonia7 cities48.7
- 5Thailand9 cities31.8
- 6China3 cities29.5
- 7Romania8 cities24.7
- 8Hungary7 cities24.0
- 9Bulgaria5 cities23.9
- 10Slovakia27 cities23.8
- 11Italy24 cities, was 2820.4
- 12Mexico45 cities, was 1118.0
- 13Chile44 cities17.2
- 14Czechia34 cities16.9
- 15Hong Kong13 cities15.2
- 16Greece9 cities13.8
- 17Austria29 cities13.1
- 18France131 cities11.9
- 19Spain107 cities11.0
- 20Belgium41 cities10.7
+ 16 more countries, 9.4 µg/m³ and below
- 27United States762 cities7.4
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.