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 30 Nov 2024: Pakistan 111.1 µg/m³, India 91.1 µg/m³ and Bosnia and Herzegovina 73.9 µg/m³.
- 1Pakistan4 cities111.1
- 2India5 cities91.1
- 3Bosnia and Herzegovina4 cities73.9
- 4Serbia25 cities46.7
- 5China3 cities26.1
- 6Thailand16 cities25.3
- 7Slovenia11 cities25.1
- 8Romania10 cities24.2
- 9Hungary11 cities22.2
- 10Slovakia39 cities20.7
- 11Poland76 cities20.6
- 12Chile47 cities18.6
- 13Czechia36 cities17.9
- 14Mexico12 cities17.9
- 15Bulgaria8 cities17.8
- 16Peru15 cities17.8
- 17Hong Kong13 cities17.6
- 18South Korea141 cities14.4
- 19United Kingdom5 cities, was 6312.8
- 20Singapore5 cities12.2
+ 23 more countries, 10.8 µg/m³ and below
- 36United States824 cities6.2
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.