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 Dec 2024: Pakistan 98.0 µg/m³, India 65.2 µg/m³ and China 42.7 µg/m³.
- 1Pakistan3 cities98.0
- 2India5 cities65.2
- 3China3 cities42.7
- 4Hungary5 cities34.5
- 5Thailand16 cities32.6
- 6Serbia23 cities32.3
- 7Hong Kong13 cities26.3
- 8Poland73 cities22.9
- 9Bulgaria5 cities21.1
- 10Peru18 cities20.2
- 11Chile45 cities18.4
- 12Mexico11 cities15.9
- 13Taiwan43 cities12.4
- 14South Korea140 cities11.8
- 15Singapore5 cities10.5
- 16United States810 cities7.4
- 17Norway18 cities7.3
- 18Japan523 cities7.0
- 19The Netherlands21 cities6.2
- 20United Kingdom6 cities5.8
+ 5 more countries, 5.5 µg/m³ and below
Not counted on this day, too few cities measured: Lithuania since 7 Dec 2024, Puerto Rico since 7 Dec 2024, Bosnia and Herzegovina since 2 Dec 2024 and 21 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.