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 2 May 2024: Laos 65.1 µg/m³, India 46.0 µg/m³ and China 38.1 µg/m³.
- 1Laos3 cities65.1
- 2India5 cities46.0
- 3China4 cities38.1
- 4Pakistan3 cities30.5
- 5Thailand82 cities, was 1530.3
- 6Chile46 cities26.3
- 7Peru6 cities24.7
- 8South Korea141 cities19.8
- 9Mexico11 cities19.3
- 10Taiwan43 cities18.5
- 11Serbia24 cities13.6
- 12Hong Kong12 cities, was 1313.5
- 13Poland75 cities11.9
- 14North Macedonia9 cities11.6
- 15Malta5 cities11.6
- 16Greece7 cities11.5
- 17Japan519 cities11.3
- 18Singapore5 cities10.8
- 19Slovakia16 cities10.8
- 20Italy39 cities, was 399.2
+ 26 more countries, 9.0 µg/m³ and below
- 39United States797 cities5.5
Not counted on this day, too few cities measured: Bosnia and Herzegovina since 2 May 2024, Montenegro since 26 Mar 2024, Switzerland since 20 Mar 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.