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 15 Mar 2024: Pakistan 72.0 µg/m³, China 60.1 µg/m³ and India 57.8 µg/m³.
- 1Pakistan3 cities72.0
- 2China3 cities60.1
- 3India5 cities57.8
- 4Poland67 cities26.9
- 5Thailand16 cities, was 7825.1
- 6Serbia14 cities22.4
- 7Chile44 cities18.1
- 8Peru6 cities16.1
- 9Mexico12 cities14.6
- 10Singapore5 cities13.8
- 11Montenegro3 cities13.1
- 12United Kingdom58 cities, was 5910.6
- 13Bulgaria5 cities9.6
- 14Japan508 cities9.1
- 15United States767 cities5.6
- 16Canada108 cities4.5
Not counted on this day, too few cities measured: Taiwan since 14 Mar 2024, Austria since 13 Mar 2024, Belgium since 13 Mar 2024 and 27 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.