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 19 Mar 2024: Pakistan 60.7 µg/m³, China 45.2 µg/m³ and India 44.2 µg/m³.
- 1Pakistan4 cities60.7
- 2China4 cities45.2
- 3India4 cities44.2
- 4Serbia10 cities27.5
- 5Thailand19 cities, was 7824.1
- 6Hong Kong13 cities22.5
- 7Poland72 cities20.6
- 8Chile45 cities19.7
- 9Peru6 cities17.1
- 10Mexico12 cities14.5
- 11Montenegro3 cities13.1
- 12Bulgaria5 cities12.1
- 13Singapore5 cities11.7
- 14Japan522 cities11.6
- 15Hungary3 cities, was 1011.0
- 16The Netherlands22 cities7.9
- 17Norway18 cities6.6
- 18Australia19 cities6.1
- 19United States771 cities6.0
- 20Canada109 cities5.3
+ 2 more countries, 4.8 µg/m³ and below
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 21 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.