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 17 Aug 2024: Chile 42.7 µg/m³, Pakistan 33.9 µg/m³ and China 23.2 µg/m³.
- 1Chile44 cities42.7
- 2Pakistan4 cities33.9
- 3China4 cities23.2
- 4Peru16 cities21.0
- 5India4 cities18.3
- 6New Zealand5 cities15.4
- 7Singapore5 cities14.9
- 8Malta5 cities14.0
- 9North Macedonia9 cities13.4
- 10Italy10 cities13.2
- 11Thailand50 cities11.7
- 12Martinique3 cities11.1
- 13Greece5 cities11.0
- 14Slovakia41 cities11.0
- 15Serbia18 cities10.3
- 16Hong Kong13 cities9.6
- 17Japan556 cities9.5
- 18South Korea140 cities9.3
- 19Mexico3 cities9.1
- 20Canada118 cities9.0
+ 23 more countries, 9.0 µg/m³ and below
- 23United States801 cities8.9
Not counted on this day, too few cities measured: Estonia since 17 Aug 2024, Luxembourg since 16 Aug 2024, Czechia since 7 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.