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 22 Jan 2024: Pakistan 234.4 µg/m³, India 73.9 µg/m³ and North Macedonia 42.1 µg/m³.
- 1Pakistan4 cities234.4
- 2India5 cities73.9
- 3North Macedonia7 cities42.1
- 4Thailand64 cities, was 1041.1
- 5China3 cities40.0
- 6Peru5 cities31.8
- 7Serbia12 cities, was 329.2
- 8Montenegro3 cities28.5
- 9Poland78 cities23.1
- 10Romania8 cities22.3
- 11Bulgaria6 cities21.4
- 12Czechia37 cities, was 3019.9
- 13Greece10 cities19.5
- 14Hungary9 cities19.3
- 15Slovakia27 cities18.6
- 16Chile45 cities18.5
- 17Austria28 cities17.5
- 18Italy22 cities17.0
- 19Norway21 cities16.2
- 20Hong Kong13 cities16.1
+ 20 more countries, 14.9 µg/m³ and below
- 32United States767 cities7.1
Not counted on this day, too few cities measured: Singapore since 21 Jan 2024, Reunion since 15 Jan 2024, Malta since 2 Jan 2024 and Martinique since 1 Dec 2023.
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.