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 21 Mar 2024: Pakistan 55.5 µg/m³, India 43.4 µg/m³ and China 41.9 µg/m³.
- 1Pakistan4 cities55.5
- 2India4 cities43.4
- 3China4 cities41.9
- 4Serbia10 cities30.1
- 5Thailand16 cities, was 7825.4
- 6Taiwan42 cities24.6
- 7Hong Kong12 cities23.2
- 8Poland72 cities22.0
- 9Chile45 cities20.9
- 10Peru6 cities18.8
- 11Montenegro3 cities13.9
- 12Bulgaria5 cities13.8
- 13Mexico11 cities12.7
- 14Japan515 cities11.8
- 15Hungary3 cities, was 1011.7
- 16Singapore5 cities11.7
- 17Australia19 cities5.7
- 18United Kingdom11 cities, was 595.6
- 19Norway18 cities4.9
- 20United States764 cities4.9
+ 1 more country, at 4.1 µg/m³
Not counted on this day, too few cities measured: Iceland since 21 Mar 2024, The Netherlands since 21 Mar 2024, Austria since 13 Mar 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.