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 25 Mar 2024: Pakistan 48.5 µg/m³, India 43.8 µg/m³ and China 37.5 µg/m³.
- 1Pakistan4 cities48.5
- 2India4 cities43.8
- 3China4 cities37.5
- 4Thailand18 cities, was 7829.2
- 5Serbia10 cities28.3
- 6Poland75 cities22.1
- 7Chile43 cities19.2
- 8Taiwan42 cities18.6
- 9Mexico12 cities14.9
- 10Singapore5 cities12.4
- 11Bulgaria5 cities9.7
- 12Japan491 cities8.4
- 13United Kingdom4 cities, was 596.9
- 14Norway19 cities5.8
- 15Australia3 cities, was 205.5
- 16United States773 cities5.5
- 17Canada106 cities4.2
Not counted on this day, too few cities measured: Peru since 23 Mar 2024, Hong Kong since 22 Mar 2024, Hungary since 22 Mar 2024 and 26 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.