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 Dec 2025: Pakistan 243.4 µg/m³, India 62.0 µg/m³ and North Macedonia 41.2 µg/m³.
- 1Pakistan13 cities243.4
- 2India243 cities62.0
- 3North Macedonia13 cities41.2
- 4Bosnia and Herzegovina4 cities38.2
- 5Ghana3 cities32.1
- 6Hong Kong13 cities27.0
- 7Peru6 cities26.1
- 8Montenegro4 cities23.5
- 9Thailand70 cities23.5
- 10Romania17 cities20.7
- 11Slovenia12 cities, was 1220.6
- 12South Korea136 cities20.4
- 13Mexico51 cities19.9
- 14Bulgaria7 cities19.4
- 15Hungary12 cities19.2
- 16Poland68 cities19.0
- 17Chile44 cities16.5
- 18Laos3 cities16.1
- 19Taiwan45 cities14.4
- 20Slovakia17 cities, was 3313.5
+ 26 more countries, 12.4 µg/m³ and below
- 34United States856 cities, was 8697.4
Not counted on this day, too few cities measured: Ireland since 11 Dec 2025, Philippines since 10 Dec 2025, Serbia since 4 Dec 2025 and 3 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.