Pollution

Johnson appears before Environmental Audit Committee, as Labour confirms plan for national network of low emissions zones

London Mayor wants return of scrappage scheme to encourage switch to less polluting cars

Effects of China's 'war on pollution' are already being felt, according to state media

Toxic metal threatens marine life as it accumulates faster in shallow layers than in deep sea due to human activity

Party is committed to planting 3.5m trees if they stay in power in attempt to woo back voters from the Greens and Labour

Boris Johnson calls on Westminster government to step up efforts to tackle UK's dangerously high pollution levels with new manifesto

Diesel vehicles expected to face £10 charge from 2020 to enter capital's planned ultra low emission zone

New scheme launches in Victoria after Mayor branded claims Oxford Street has world's worst NO2 levels as 'b*ll*cks'

Government to buy nearly 300 plug-in vehicles as it puts 'money where its mouth is'

Defra predicts many cities will not comply with EU limits for at least another decade