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 17 Dec 2023: Pakistan 132.4 µg/m³, India 99.3 µg/m³ and China 35.9 µg/m³.
- 1Pakistan4 cities132.4
- 2India4 cities99.3
- 3China3 cities35.9
- 4North Macedonia7 cities34.5
- 5Thailand9 cities32.2
- 6Serbia3 cities26.4
- 7Hong Kong13 cities20.9
- 8Slovakia27 cities19.0
- 9Bulgaria5 cities18.3
- 10Czechia34 cities17.8
- 11Chile39 cities17.7
- 12Mexico44 cities, was 1117.4
- 13Romania8 cities16.2
- 14Hungary7 cities16.1
- 15Greece8 cities15.3
- 16Italy23 cities14.7
- 17Lithuania3 cities14.4
- 18Austria29 cities13.3
- 19Belgium41 cities10.4
- 20Ireland3 cities9.9
+ 16 more countries, 9.6 µg/m³ and below
- 28United States756 cities7.5
Not counted on this day, too few cities measured: Martinique since 8 Dec 2023 and Peru since 21 Oct 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.