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 15 Jun 2024: China 25.3 µg/m³, Peru 23.7 µg/m³ and India 23.5 µg/m³.
- 1China4 cities25.3
- 2Peru12 cities23.7
- 3India4 cities23.5
- 4Chile41 cities20.5
- 5South Korea141 cities19.6
- 6New Zealand5 cities15.1
- 7Mexico6 cities14.6
- 8Serbia24 cities12.9
- 9Singapore5 cities12.5
- 10Greece6 cities12.3
- 11Thailand70 cities12.1
- 12North Macedonia8 cities11.5
- 13Italy9 cities, was 3810.3
- 14Malta5 cities10.3
- 15Japan557 cities9.2
- 16Poland70 cities8.6
- 17Romania8 cities8.5
- 18Hungary11 cities8.3
- 19Slovakia38 cities8.0
- 20Bulgaria8 cities7.9
+ 21 more countries, 7.6 µg/m³ and below
- 29United States802 cities6.4
Not counted on this day, too few cities measured: Switzerland since 6 Jun 2024, Iceland since 6 Jun 2024, Czechia since 3 Jun 2024 and 7 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.