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 19 Feb 2024: Pakistan 125.2 µg/m³, India 76.3 µg/m³ and North Macedonia 49.6 µg/m³.
- 1Pakistan4 cities125.2
- 2India5 cities76.3
- 3North Macedonia9 cities49.6
- 4China3 cities49.5
- 5Serbia18 cities, was 340.4
- 6Montenegro3 cities40.0
- 7Thailand74 cities, was 939.3
- 8Italy33 cities29.7
- 9Peru6 cities19.4
- 10Chile45 cities19.3
- 11Hong Kong13 cities18.9
- 12Bulgaria6 cities18.4
- 13Romania9 cities18.3
- 14Slovakia41 cities16.9
- 15Greece10 cities15.9
- 16Poland78 cities15.6
- 17Hungary10 cities15.2
- 18South Africa10 cities14.1
- 19Czechia38 cities13.5
- 20Mexico11 cities, was 4412.4
+ 21 more countries, 12.3 µg/m³ and below
- 37United States780 cities6.7
Not counted on this day, too few cities measured: Reunion since 20 Jan 2024 and Malta since 6 Jan 2024. Days missing from the source archive fall in this window, so fewer countries are counted.
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.