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 3 Jun 2024: Chile 51.4 µg/m³, India 35.9 µg/m³ and China 25.1 µg/m³.
- 1Chile46 cities51.4
- 2India3 cities35.9
- 3China3 cities25.1
- 4Mexico13 cities22.6
- 5Peru12 cities21.8
- 6New Zealand5 cities15.1
- 7Finland16 cities12.4
- 8Poland73 cities11.7
- 9South Korea141 cities11.6
- 10Lithuania4 cities11.6
- 11Latvia4 cities11.4
- 12Thailand76 cities11.4
- 13Greece6 cities11.0
- 14Malta5 cities10.6
- 15Sweden17 cities9.7
- 16Singapore5 cities9.7
- 17Serbia23 cities9.4
- 18North Macedonia9 cities9.2
- 19Taiwan42 cities9.0
- 20Hong Kong11 cities, was 118.8
+ 22 more countries, 8.6 µg/m³ and below
- 35United States793 cities5.7
Not counted on this day, too few cities measured: Czechia since 3 Jun 2024, Pakistan since 2 Jun 2024, Estonia since 1 Jun 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.