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 30 days to 28 Mar 2024: Pakistan 56.3 µg/m³, India 47.0 µg/m³ and China 45.7 µg/m³.
- 1Pakistan4 cities56.3
- 2India5 cities47.0
- 3China3 cities45.7
- 4Thailand14 cities, was 7225.1
- 5Poland74 cities25.0
- 6Serbia14 cities23.0
- 7Taiwan43 cities20.2
- 8Chile42 cities19.3
- 9Mexico12 cities15.4
- 10Bulgaria4 cities14.7
- 11Hungary3 cities, was 913.0
- 12Singapore5 cities11.6
- 13The Netherlands20 cities8.9
- 14Japan499 cities8.3
- 15Norway18 cities8.2
- 16United Kingdom50 cities8.0
- 17United States777 cities5.5
- 18Canada111 cities4.9
- 19Iceland4 cities3.1
Not counted on this day, too few cities measured: Hong Kong since 26 Mar 2024, Montenegro since 26 Mar 2024, Australia since 25 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.