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 10 Oct 2024: Pakistan 51.2 µg/m³, China 31.0 µg/m³ and India 30.6 µg/m³.
- 1Pakistan4 cities51.2
- 2China4 cities31.0
- 3India5 cities30.6
- 4Peru17 cities22.5
- 5Chile46 cities21.5
- 6Thailand22 cities, was 6621.5
- 7Hong Kong13 cities18.8
- 8Serbia24 cities15.1
- 9Singapore5 cities14.0
- 10Poland72 cities12.0
- 11South Korea140 cities11.1
- 12Hungary4 cities10.2
- 13Taiwan43 cities8.3
- 14United States799 cities7.2
- 15Bulgaria5 cities6.1
- 16Australia35 cities5.9
- 17United Kingdom62 cities5.2
- 18The Netherlands22 cities5.0
- 19Norway17 cities4.6
- 20Japan535 cities4.5
+ 3 more countries, 4.4 µg/m³ and below
Not counted on this day, too few cities measured: Mexico since 19 Sep 2024, Belgium since 17 Aug 2024, Switzerland since 17 Aug 2024 and 18 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.