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 13 Aug 2024: Chile 43.0 µg/m³, Pakistan 27.0 µg/m³ and China 20.8 µg/m³.
- 1Chile43 cities43.0
- 2Pakistan4 cities27.0
- 3China3 cities20.8
- 4India5 cities18.8
- 5Peru15 cities18.2
- 6Italy12 cities14.1
- 7Malta5 cities14.0
- 8South Korea140 cities13.2
- 9New Zealand5 cities12.6
- 10Singapore5 cities11.8
- 11Slovakia41 cities11.6
- 12Hong Kong12 cities11.1
- 13Thailand69 cities, was 911.1
- 14Taiwan43 cities11.0
- 15North Macedonia9 cities10.9
- 16Spain88 cities9.5
- 17Martinique3 cities9.4
- 18Greece10 cities9.1
- 19Japan556 cities8.6
- 20Hungary9 cities8.4
+ 24 more countries, 8.4 µg/m³ and below
- 26United States793 cities7.2
Not counted on this day, too few cities measured: Ireland since 11 Aug 2024, Luxembourg since 10 Aug 2024, Czechia since 1 Aug 2024 and 2 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.