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 30 days to 13 Apr 2024: Laos 62.4 µg/m³, Pakistan 44.6 µg/m³ and India 43.1 µg/m³.
- 1Laos3 cities62.4
- 2Pakistan4 cities44.6
- 3India5 cities43.1
- 4China4 cities42.1
- 5Thailand77 cities, was 7233.4
- 6Chile44 cities22.3
- 7Taiwan43 cities21.6
- 8Serbia21 cities17.3
- 9Poland75 cities16.4
- 10Mexico11 cities15.9
- 11Peru4 cities15.4
- 12Singapore5 cities11.1
- 13Hungary3 cities, was 910.9
- 14Japan510 cities10.0
- 15Bulgaria5 cities8.4
- 16United Kingdom6 cities, was 606.5
- 17Norway19 cities6.4
- 18The Netherlands33 cities6.2
- 19United States781 cities5.4
- 20Australia21 cities4.3
+ 2 more countries, 4.1 µg/m³ and below
Not counted on this day, too few cities measured: Hong Kong since 26 Mar 2024, Montenegro since 26 Mar 2024, Belgium since 20 Mar 2024 and 20 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.