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 12 Jun 2024: Chile 51.3 µg/m³, India 29.0 µg/m³ and Mexico 23.9 µg/m³.
- 1Chile45 cities51.3
- 2India4 cities29.0
- 3Mexico11 cities23.9
- 4Peru11 cities23.2
- 5China3 cities21.9
- 6New Zealand5 cities16.3
- 7Malta5 cities15.6
- 8South Korea141 cities14.8
- 9Thailand75 cities13.0
- 10Greece7 cities12.8
- 11Taiwan43 cities11.7
- 12Italy15 cities11.3
- 13Serbia24 cities10.7
- 14Poland72 cities10.6
- 15Latvia4 cities10.3
- 16Singapore5 cities10.1
- 17Hong Kong10 cities9.9
- 18Lithuania4 cities9.7
- 19North Macedonia9 cities9.7
- 20Belgium44 cities9.6
+ 22 more countries, 9.1 µg/m³ and below
- 35United States802 cities6.2
Not counted on this day, too few cities measured: Czechia since 11 Jun 2024, Pakistan since 9 Jun 2024, Estonia since 8 Jun 2024 and 4 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.