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 20 Mar 2024: Pakistan 60.6 µg/m³, India 44.2 µg/m³ and China 42.3 µg/m³.
- 1Pakistan4 cities60.6
- 2India4 cities44.2
- 3China4 cities42.3
- 4Serbia10 cities29.3
- 5Taiwan41 cities24.8
- 6Thailand19 cities, was 7824.5
- 7Hong Kong13 cities22.4
- 8Poland72 cities21.4
- 9Chile44 cities20.6
- 10Peru6 cities17.6
- 11Montenegro3 cities13.4
- 12Mexico11 cities13.2
- 13Bulgaria5 cities13.1
- 14Japan524 cities11.8
- 15Singapore5 cities11.8
- 16Hungary3 cities, was 1011.2
- 17The Netherlands22 cities7.8
- 18Australia20 cities5.9
- 19United States763 cities5.5
- 20Norway18 cities5.1
+ 3 more countries, 5.0 µg/m³ and below
Not counted on this day, too few cities measured: Austria since 13 Mar 2024, Belgium since 13 Mar 2024, Switzerland since 13 Mar 2024 and 20 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.