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 14 Feb 2024: Pakistan 149.8 µg/m³, India 67.5 µg/m³ and China 53.3 µg/m³.
- 1Pakistan4 cities149.8
- 2India5 cities67.5
- 3China3 cities53.3
- 4North Macedonia7 cities48.4
- 5Montenegro3 cities39.1
- 6Thailand68 cities, was 937.9
- 7Serbia12 cities, was 336.2
- 8Italy22 cities22.0
- 9Peru5 cities21.3
- 10Romania8 cities21.0
- 11Bulgaria6 cities19.0
- 12Hong Kong13 cities19.0
- 13Chile45 cities18.6
- 14Greece10 cities17.3
- 15Poland76 cities16.9
- 16Slovakia24 cities15.9
- 17Czechia37 cities14.2
- 18Hungary9 cities14.2
- 19South Africa9 cities12.9
- 20Mexico11 cities, was 4412.8
+ 21 more countries, 12.2 µg/m³ and below
- 37United States778 cities6.9
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.