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 21 Nov 2024: Pakistan 107.4 µg/m³, India 82.6 µg/m³ and Bosnia and Herzegovina 49.3 µg/m³.
- 1Pakistan4 cities107.4
- 2India5 cities82.6
- 3Bosnia and Herzegovina3 cities49.3
- 4Serbia25 cities44.7
- 5Romania10 cities26.7
- 6Thailand16 cities25.5
- 7China3 cities24.0
- 8Hungary10 cities23.7
- 9Poland77 cities22.3
- 10Slovakia41 cities21.4
- 11Czechia36 cities19.4
- 12Chile46 cities19.0
- 13Hong Kong13 cities18.0
- 14Peru17 cities17.6
- 15Mexico12 cities, was 316.4
- 16Bulgaria8 cities16.2
- 17South Korea141 cities14.7
- 18Singapore6 cities14.7
- 19United Kingdom5 cities, was 6312.6
- 20Belgium45 cities12.4
+ 22 more countries, the next at 10.9 µg/m³
- 35United States823 cities6.4
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.