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 14 Jun 2024: China 24.5 µg/m³, India 23.8 µg/m³ and Chile 22.4 µg/m³.
- 1China4 cities24.5
- 2India4 cities23.8
- 3Chile44 cities22.4
- 4Peru12 cities22.2
- 5South Korea140 cities18.7
- 6Mexico11 cities17.0
- 7New Zealand5 cities14.4
- 8Serbia24 cities13.2
- 9Greece6 cities12.9
- 10Singapore5 cities12.2
- 11North Macedonia8 cities11.8
- 12Thailand70 cities11.8
- 13Italy15 cities11.7
- 14Malta5 cities10.1
- 15Japan558 cities9.1
- 16Poland70 cities9.0
- 17Romania8 cities8.9
- 18Hungary11 cities8.3
- 19Slovakia38 cities8.2
- 20Bosnia and Herzegovina4 cities8.1
+ 21 more countries, 7.8 µg/m³ and below
- 30United States795 cities6.2
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.