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 Feb 2024: Pakistan 157.0 µg/m³, India 66.3 µg/m³ and China 52.5 µg/m³.
- 1Pakistan4 cities157.0
- 2India5 cities66.3
- 3China3 cities52.5
- 4North Macedonia7 cities49.7
- 5Montenegro3 cities41.1
- 6Thailand69 cities, was 936.9
- 7Serbia12 cities, was 336.0
- 8Italy22 cities23.0
- 9Romania8 cities22.0
- 10Peru5 cities21.9
- 11Bulgaria6 cities19.9
- 12Hong Kong13 cities18.9
- 13Chile45 cities18.5
- 14Greece10 cities18.0
- 15Poland76 cities16.6
- 16Slovakia24 cities16.0
- 17Hungary9 cities14.7
- 18Czechia37 cities14.0
- 19Mexico11 cities, was 4412.9
- 20South Africa9 cities12.9
+ 21 more countries, 12.3 µg/m³ and below
- 37United States777 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.