Air quality alerts have been issued by Mayor of London Sadiq Khan – with moderate pollution expected until the weekend across 17 London boroughs.
The problem is expected to peak on Thursday in Westminster, City of London, Hammersmith, Kensington and Chelsea, Kingston and Wandsworth.
Pollution warnings will be displayed at bus stops, Tube stations and roadsides.
London breached its legal limits for toxic air for the entire year in the first five days of 2017.
Notices will be displayed at bus stops, river pier stops, Tube stations and on signs on London’s busiest roads.
