Transport for London's #ULEZ scheme cleaned London's air:
Gas boilers now biggest source of #AirPollution in central #London, study shows
"The findings highlight the success of transport interventions, such as the London Low Emission Zone and the Ultra Low Emission Zone (ULEZ), in significantly reducing #NOx emissions from vehicles."
https://phys.org/news/2025-04-gas-boilers-biggest-source-air.html
#TfL