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 14 Oct 2024: Pakistan 69.4 µg/m³, China 35.2 µg/m³ and India 33.6 µg/m³.
- 1Pakistan4 cities69.4
- 2China4 cities35.2
- 3India5 cities33.6
- 4Thailand22 cities, was 6621.5
- 5Peru17 cities21.3
- 6Chile46 cities19.9
- 7Hong Kong13 cities19.8
- 8Serbia22 cities14.3
- 9South Korea141 cities13.9
- 10Hungary4 cities12.5
- 11Singapore5 cities12.3
- 12Mexico12 cities, was 311.5
- 13Taiwan43 cities11.1
- 14Poland71 cities10.4
- 15United States752 cities6.9
- 16Japan531 cities6.4
- 17Bulgaria5 cities6.3
- 18Australia36 cities5.9
- 19The Netherlands22 cities5.2
- 20United Kingdom63 cities4.6
+ 4 more countries, 4.1 µg/m³ and below
Not counted on this day, too few cities measured: Belgium since 17 Aug 2024, Switzerland since 17 Aug 2024, Germany since 17 Aug 2024 and 15 more countries.
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.