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 22 Mar 2024: Pakistan 55.8 µg/m³, India 43.3 µg/m³ and China 36.8 µg/m³.
- 1Pakistan4 cities55.8
- 2India4 cities43.3
- 3China4 cities36.8
- 4Serbia10 cities31.9
- 5Thailand11 cities, was 7829.6
- 6Taiwan43 cities24.6
- 7Poland72 cities21.8
- 8Chile45 cities21.2
- 9Peru5 cities17.1
- 10Bulgaria5 cities14.1
- 11Mexico11 cities13.3
- 12Singapore5 cities12.8
- 13Japan513 cities10.3
- 14United Kingdom4 cities, was 596.5
- 15United States763 cities5.1
- 16Norway18 cities4.7
- 17Canada107 cities4.0
Not counted on this day, too few cities measured: Australia since 22 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.