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 13 Jul 2025: Chile 41.0 µg/m³, Pakistan 37.7 µg/m³ and Peru 30.4 µg/m³.
- 1Chile48 cities41.0
- 2Pakistan11 cities37.7
- 3Peru5 cities30.4
- 4India215 cities21.5
- 5Japan553 cities15.7
- 6Mexico42 cities15.7
- 7South Korea140 cities14.2
- 8Martinique3 cities13.9
- 9New Zealand10 cities11.3
- 10Hong Kong12 cities10.2
- 11Romania11 cities8.8
- 12Greece7 cities8.2
- 13Spain123 cities, was 998.0
- 14Italy19 cities, was 98.0
- 15Hungary11 cities7.9
- 16Lithuania4 cities7.9
- 17Malta5 cities7.8
- 18United States829 cities7.7
- 19Latvia4 cities7.5
- 20Poland59 cities7.4
+ 21 more countries, 7.0 µg/m³ and below
Not counted on this day, too few cities measured: Luxembourg since 10 Jul 2025, Czechia since 3 Jul 2025, Serbia since 3 Jul 2025 and 4 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.