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 9 Nov 2024: Pakistan 127.3 µg/m³, India 71.1 µg/m³ and Serbia 53.6 µg/m³.
- 1Pakistan4 cities127.3
- 2India5 cities71.1
- 3Serbia24 cities53.6
- 4Romania8 cities39.1
- 5Czechia33 cities31.7
- 6Hungary9 cities, was 430.0
- 7China3 cities29.3
- 8Poland77 cities28.5
- 9Slovakia38 cities24.7
- 10Thailand16 cities23.6
- 11United Kingdom6 cities, was 6223.5
- 12Hong Kong13 cities23.1
- 13Mexico14 cities, was 320.4
- 14Chile46 cities20.0
- 15Belgium44 cities16.6
- 16The Netherlands23 cities16.3
- 17Bulgaria8 cities15.9
- 18Peru18 cities15.8
- 19Singapore5 cities14.8
- 20South Korea141 cities14.1
+ 19 more countries, 13.9 µg/m³ and below
- 33United States815 cities6.1
Not counted on this day, too few cities measured: Bosnia and Herzegovina since 9 Nov 2024, Martinique since 9 Nov 2024, Estonia since 3 Nov 2024 and 2 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.