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 16 Aug 2024: Chile 42.6 µg/m³, Pakistan 27.8 µg/m³ and Peru 21.2 µg/m³.
- 1Chile41 cities42.6
- 2Pakistan4 cities27.8
- 3Peru15 cities21.2
- 4India5 cities18.6
- 5China3 cities16.9
- 6Italy8 cities15.7
- 7Slovakia40 cities13.2
- 8Singapore5 cities13.0
- 9Malta5 cities12.7
- 10New Zealand5 cities12.7
- 11South Korea140 cities11.9
- 12North Macedonia9 cities11.5
- 13Serbia10 cities11.3
- 14Thailand72 cities, was 910.9
- 15Greece9 cities10.1
- 16Canada113 cities9.7
- 17Hong Kong12 cities9.4
- 18Spain78 cities9.2
- 19Hungary9 cities9.1
- 20Japan561 cities9.0
+ 20 more countries, 8.8 µg/m³ and below
- 23United States793 cities8.3
Not counted on this day, too few cities measured: Latvia since 16 Aug 2024, Martinique since 16 Aug 2024, Estonia since 15 Aug 2024 and 6 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.