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 14 Dec 2024: Pakistan 104.4 µg/m³, India 62.4 µg/m³ and Bosnia and Herzegovina 35.4 µg/m³.
- 1Pakistan3 cities104.4
- 2India5 cities62.4
- 3Bosnia and Herzegovina4 cities35.4
- 4China4 cities35.1
- 5Serbia25 cities33.3
- 6Thailand16 cities28.4
- 7Hong Kong13 cities23.2
- 8Slovenia12 cities21.4
- 9Mexico11 cities20.7
- 10Chile45 cities19.0
- 11Bulgaria8 cities18.8
- 12Poland75 cities18.2
- 13Croatia6 cities17.6
- 14Peru17 cities17.6
- 15South Korea141 cities16.8
- 16Hungary11 cities16.1
- 17Belgium45 cities15.1
- 18Greece9 cities15.0
- 19Slovakia42 cities14.1
- 20Austria35 cities14.0
+ 26 more countries, 12.8 µg/m³ and below
- 36United States815 cities6.8
Not counted on this day, too few cities measured: Puerto Rico since 7 Dec 2024, Luxembourg since 1 Dec 2024, Kosovo since 24 Nov 2024 and Italy since 27 Oct 2024.
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.