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 23 Nov 2024: India 104.9 µg/m³, Pakistan 95.4 µg/m³ and Bosnia and Herzegovina 59.1 µg/m³.
- 1India5 cities104.9
- 2Pakistan4 cities95.4
- 3Bosnia and Herzegovina4 cities59.1
- 4Serbia25 cities40.2
- 5China3 cities25.8
- 6Slovenia12 cities23.9
- 7Thailand16 cities21.9
- 8Kosovo9 cities21.9
- 9Romania10 cities20.5
- 10Chile45 cities18.2
- 11Croatia5 cities18.2
- 12Peru15 cities18.0
- 13Bulgaria8 cities17.7
- 14Hungary10 cities17.7
- 15South Korea141 cities16.4
- 16Slovakia39 cities15.1
- 17Mexico11 cities14.4
- 18Greece9 cities14.1
- 19Hong Kong11 cities13.1
- 20Poland75 cities13.0
+ 26 more countries, 9.8 µg/m³ and below
- 34United States815 cities5.7
Not counted on this day, too few cities measured: Lithuania since 21 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.