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 6 Dec 2025: Pakistan 221.3 µg/m³, India 61.5 µg/m³ and Bosnia and Herzegovina 45.7 µg/m³.
- 1Pakistan13 cities221.3
- 2India242 cities61.5
- 3Bosnia and Herzegovina5 cities45.7
- 4North Macedonia9 cities40.6
- 5Montenegro4 cities34.7
- 6Thailand73 cities30.5
- 7Laos3 cities28.9
- 8Hong Kong13 cities27.9
- 9Poland63 cities26.2
- 10Ghana4 cities24.9
- 11Peru5 cities23.9
- 12Mexico50 cities23.7
- 13Slovenia12 cities, was 1221.5
- 14Philippines3 cities21.0
- 15Slovakia5 cities, was 3319.4
- 16Hungary11 cities19.3
- 17Chile41 cities16.5
- 18Bulgaria4 cities15.6
- 19Austria38 cities, was 3714.0
- 20South Korea138 cities13.6
+ 19 more countries, 13.3 µg/m³ and below
- 27United States871 cities, was 8697.9
Not counted on this day, too few cities measured: Serbia since 4 Dec 2025, Senegal since 4 Dec 2025, Ireland since 30 Nov 2025 and 11 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.