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 17 Oct 2024: Pakistan 76.9 µg/m³, China 32.1 µg/m³ and India 31.1 µg/m³.
- 1Pakistan4 cities76.9
- 2China4 cities32.1
- 3India5 cities31.1
- 4Peru17 cities22.3
- 5Chile46 cities21.1
- 6Thailand20 cities, was 6620.4
- 7Serbia22 cities17.6
- 8Hong Kong13 cities15.9
- 9Hungary4 cities14.4
- 10South Korea138 cities14.4
- 11Mexico12 cities, was 313.8
- 12Singapore5 cities12.6
- 13Poland72 cities12.2
- 14Taiwan42 cities12.2
- 15Japan532 cities8.2
- 16The Netherlands22 cities6.6
- 17Bulgaria5 cities6.4
- 18United States741 cities6.2
- 19United Kingdom63 cities6.1
- 20Norway18 cities5.8
+ 4 more countries, 5.8 µg/m³ and below
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.