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 19 Aug 2024: Chile 37.5 µg/m³, Pakistan 23.5 µg/m³ and Peru 22.5 µg/m³.
- 1Chile43 cities37.5
- 2Pakistan3 cities23.5
- 3Peru16 cities22.5
- 4India5 cities18.6
- 5China4 cities17.1
- 6New Zealand5 cities13.5
- 7Singapore5 cities13.5
- 8Serbia10 cities13.4
- 9Thailand17 cities, was 912.7
- 10Hungary5 cities12.3
- 11Canada115 cities10.3
- 12South Korea140 cities10.1
- 13Poland69 cities10.0
- 14Japan560 cities8.9
- 15Hong Kong12 cities8.8
- 16United States798 cities8.5
- 17The Netherlands20 cities7.0
- 18Mexico3 cities6.5
- 19Taiwan43 cities6.4
- 20United Kingdom62 cities6.2
+ 4 more countries, 5.5 µg/m³ and below
Not counted on this day, too few cities measured: Belgium since 17 Aug 2024, Switzerland since 17 Aug 2024, Germany since 17 Aug 2024 and 22 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.