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 1 Jun 2024: Chile 48.8 µg/m³, Pakistan 38.5 µg/m³ and India 33.3 µg/m³.
- 1Chile45 cities48.8
- 2Pakistan4 cities38.5
- 3India4 cities33.3
- 4China3 cities25.0
- 5Mexico10 cities23.9
- 6Peru11 cities22.5
- 7Laos3 cities22.3
- 8Thailand79 cities19.4
- 9Taiwan43 cities14.7
- 10Malta5 cities14.4
- 11New Zealand5 cities14.4
- 12South Korea141 cities14.1
- 13Hong Kong10 cities12.1
- 14Greece6 cities10.7
- 15Belgium44 cities10.6
- 16Serbia24 cities10.6
- 17Poland76 cities10.3
- 18The Netherlands36 cities10.2
- 19Latvia4 cities10.1
- 20Singapore5 cities10.0
+ 28 more countries, 9.1 µg/m³ and below
- 39United States807 cities6.0
Not counted on this day, too few cities measured: Bosnia and Herzegovina since 2 May 2024.
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.