April 2020) Toxic air over London falls by 50% at busiest traffic spots | Air pollution | The Guardian

Matthew Taylor

London has had dramatic improvements in its air quality since the coronavirus lockdown, with dangerous emissions at some of the capital’s busiest roads and junctions falling by almost 50%.
Figures released by the London mayor, Sadiq Khan, show that anti-pollution measures introduced from 2017 had already led to a 35% drop across the capital of the harmful gas nitrogen dioxide, NO2 – rising to a 44% reduction inside central London’s ultra-low emissions zone (ULEZ).
In the last four weeks of lockdown there have been further big reductions, with NO2 falling by a further 27% across London, and by almost half at some of the worst pollution hotspots.