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 28 Mar 2024: Pakistan 47.6 µg/m³, Laos 45.6 µg/m³ and India 40.8 µg/m³.
- 1Pakistan4 cities47.6
- 2Laos3 cities45.6
- 3India5 cities40.8
- 4China4 cities40.4
- 5Thailand82 cities, was 7830.5
- 6Chile44 cities20.1
- 7Serbia24 cities19.1
- 8Taiwan42 cities18.3
- 9Mexico14 cities15.0
- 10Poland74 cities14.9
- 11South Korea121 cities13.2
- 12Singapore5 cities12.6
- 13Bulgaria5 cities9.0
- 14Japan498 cities6.8
- 15Norway19 cities6.6
- 16United Kingdom57 cities, was 596.1
- 17New Zealand5 cities5.9
- 18The Netherlands22 cities5.7
- 19United States781 cities5.6
- 20Canada112 cities4.5
+ 1 more country, at 2.7 µg/m³
Not counted on this day, too few cities measured: Australia since 26 Mar 2024, Peru since 23 Mar 2024, Hong Kong since 22 Mar 2024 and 25 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.