Sadiq Khan triggers alert for high air pollution in London

Capital is given emergency warning as polluted air from the continent combines with toxic air at home

The mayor of London, Sadiq Khan, has triggered the capital's emergency air quality alert as polluted air from the continent combines with toxic air in London to create dangerous levels of pollution.

The alerts will see warnings displayed at bus stops, road signs and on the underground. Khan has also asked TV and radio stations across the capital to warn their viewers and listeners in news bulletins.