The expansion of a "clean air zone" in London has sparked protests in the UK capital. From Tuesday, owners of the most polluting vehicles will have to pay a charge to drive in the city. Protesters are frustrated that the scheme has doubled in size to include the whole of London. But the mayor says the changes are vital. London's pollution levels far exceed the recommended limits set by the World Health Organization, and the issue is becoming increasingly political.
Al Jazeera’s Neave Barker reports from London, UK.
