Evidence: https://aqicn.org/historical#!city:london https://aqicn.org/historical#!city:london Note that this shows Chinese Air Quality Index, which is differen

Evidence: https://aqicn.org/historical#!city:london https://aqicn.org/historical#!city:london Note that this shows Chinese Air Quality Index, which is different than EU AQI, which is different than US AQI, which is different than... you get the point. But at the end of the day they all use the same data.