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 14 Jul 2025: Chile 42.7 µg/m³, Pakistan 35.8 µg/m³ and Peru 31.4 µg/m³.
- 1Chile48 cities42.7
- 2Pakistan11 cities35.8
- 3Peru5 cities31.4
- 4India218 cities21.1
- 5Mexico42 cities15.4
- 6Japan556 cities13.6
- 7South Korea140 cities13.2
- 8Martinique3 cities12.9
- 9New Zealand10 cities12.7
- 10Hong Kong12 cities9.2
- 11Canada116 cities8.4
- 12Romania11 cities8.4
- 13Spain118 cities8.3
- 14Italy21 cities, was 98.2
- 15Greece7 cities8.1
- 16Finland15 cities7.8
- 17United States845 cities7.6
- 18Malta5 cities7.5
- 19Lithuania4 cities7.3
- 20Latvia4 cities7.1
+ 20 more countries, 7.0 µg/m³ and below
Not counted on this day, too few cities measured: Ireland since 14 Jul 2025, Luxembourg since 10 Jul 2025, Czechia since 3 Jul 2025 and 5 more countries.
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.