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 13 Jun 2024: Chile 48.6 µg/m³, India 28.0 µg/m³ and Mexico 23.9 µg/m³.
- 1Chile44 cities48.6
- 2India4 cities28.0
- 3Mexico11 cities23.9
- 4Peru11 cities23.2
- 5China3 cities22.2
- 6New Zealand5 cities16.2
- 7Malta5 cities15.5
- 8South Korea141 cities15.0
- 9Greece7 cities13.2
- 10Thailand73 cities12.9
- 11Italy15 cities11.4
- 12Taiwan43 cities11.4
- 13North Macedonia8 cities10.8
- 14Serbia24 cities10.8
- 15Poland72 cities10.6
- 16Latvia4 cities10.1
- 17Singapore5 cities10.0
- 18Hong Kong10 cities9.9
- 19Belgium44 cities9.6
- 20Lithuania4 cities9.6
+ 21 more countries, 9.0 µg/m³ and below
- 35United States802 cities6.3
Not counted on this day, too few cities measured: Switzerland since 13 Jun 2024, Czechia since 11 Jun 2024, Pakistan since 9 Jun 2024 and 5 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.