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 21 Nov 2024: India 93.2 µg/m³, Pakistan 83.5 µg/m³ and Bosnia and Herzegovina 57.2 µg/m³.
- 1India5 cities93.2
- 2Pakistan4 cities83.5
- 3Bosnia and Herzegovina4 cities57.2
- 4Serbia25 cities44.9
- 5Slovenia12 cities27.1
- 6China3 cities25.6
- 7Romania10 cities24.2
- 8Thailand16 cities24.0
- 9Croatia5 cities22.4
- 10Kosovo9 cities20.0
- 11Hungary10 cities, was 419.8
- 12Bulgaria8 cities19.6
- 13Chile46 cities18.0
- 14Slovakia40 cities16.8
- 15Peru15 cities16.6
- 16South Korea141 cities15.9
- 17Mexico12 cities15.8
- 18Greece9 cities14.4
- 19Poland77 cities13.1
- 20Hong Kong8 cities10.9
+ 27 more countries, the next at 10.5 µg/m³
- 37United States810 cities6.0
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, Turkey and Iran, which publish only on their own websites. We are building the reader for China's network. The networks of Turkey and Iran don't answer requests from outside their countries, so we can't read them. Most cities there are missing from this board, not clean. Why.