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 11 Aug 2024: Chile 39.8 µg/m³, Pakistan 30.4 µg/m³ and China 23.9 µg/m³.
- 1Chile42 cities39.8
- 2Pakistan4 cities30.4
- 3China4 cities23.9
- 4India5 cities17.2
- 5Malta5 cities16.8
- 6Peru15 cities16.7
- 7New Zealand5 cities16.5
- 8Hong Kong12 cities13.7
- 9South Korea140 cities12.9
- 10Italy12 cities12.3
- 11Singapore5 cities11.9
- 12Taiwan43 cities11.8
- 13Thailand71 cities11.0
- 14Greece9 cities10.9
- 15North Macedonia9 cities10.4
- 16Martinique3 cities10.1
- 17Slovakia41 cities9.6
- 18Japan549 cities9.2
- 19Poland74 cities8.7
- 20Serbia10 cities8.4
+ 23 more countries, 8.0 µg/m³ and below
- 22United States793 cities7.8
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 3 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.