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 4 Feb 2024: Pakistan 200.4 µg/m³, India 70.4 µg/m³ and China 47.9 µg/m³.
- 1Pakistan4 cities200.4
- 2India5 cities70.4
- 3China3 cities47.9
- 4North Macedonia7 cities43.9
- 5Montenegro3 cities39.2
- 6Serbia12 cities, was 338.6
- 7Thailand77 cities, was 935.4
- 8Peru5 cities24.1
- 9Romania8 cities24.0
- 10Bulgaria6 cities23.5
- 11Hong Kong13 cities23.3
- 12Poland75 cities22.8
- 13Italy22 cities20.5
- 14Czechia37 cities19.9
- 15Slovakia27 cities19.2
- 16Hungary9 cities18.5
- 17Chile44 cities18.2
- 18Norway21 cities16.9
- 19Greece10 cities16.2
- 20Austria28 cities16.1
+ 21 more countries, 14.5 µg/m³ and below
- 36United States775 cities6.7
Not counted on this day, too few cities measured: Reunion since 20 Jan 2024, Malta since 6 Jan 2024 and Martinique since 8 Dec 2023. Days missing from the source archive fall in this window, so fewer countries are counted.
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.