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 27 Feb 2024: India 57.5 µg/m³, China 35.2 µg/m³ and North Macedonia 26.9 µg/m³.
- 1India5 cities57.5
- 2China3 cities35.2
- 3North Macedonia9 cities26.9
- 4Thailand79 cities24.9
- 5Montenegro3 cities23.5
- 6Serbia24 cities22.7
- 7Romania10 cities20.5
- 8Mexico13 cities19.8
- 9Peru6 cities18.1
- 10Chile45 cities17.3
- 11Hong Kong13 cities17.3
- 12Poland78 cities16.9
- 13Bulgaria6 cities16.7
- 14Greece8 cities16.4
- 15South Africa18 cities15.9
- 16Italy40 cities15.6
- 17Latvia4 cities12.8
- 18Slovakia41 cities12.8
- 19Czechia37 cities12.1
- 20Lithuania4 cities11.7
+ 22 more countries, 11.6 µg/m³ and below
- 25United States776 cities7.8
Not counted on this day, too few cities measured: Pakistan since 25 Feb 2024, Croatia since 18 Feb 2024 and Reunion since 15 Jan 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.