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 11 Dec 2024: Pakistan 103.9 µg/m³, India 65.0 µg/m³ and Bosnia and Herzegovina 35.8 µg/m³.
- 1Pakistan3 cities103.9
- 2India5 cities65.0
- 3Bosnia and Herzegovina4 cities35.8
- 4China4 cities34.8
- 5Thailand16 cities30.4
- 6Serbia25 cities30.3
- 7Hong Kong13 cities27.6
- 8Slovenia12 cities23.7
- 9Peru18 cities19.2
- 10Poland75 cities19.1
- 11Bulgaria8 cities18.7
- 12Hungary10 cities18.4
- 13Chile45 cities18.3
- 14Croatia6 cities18.2
- 15Mexico11 cities17.0
- 16Greece9 cities16.6
- 17South Korea140 cities15.0
- 18Slovakia42 cities13.0
- 19Latvia4 cities11.6
- 20Austria35 cities11.0
+ 26 more countries, 10.5 µg/m³ and below
- 31United States808 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.