Mayor of London Sadiq Khan is on a mission to clean up London's air. He's scrapped the new Routemasters, promised to spend £875 million to fight London's pollution problem and has already launched a 'green bus zones' initiative. And now he's announced plans for two new electric-only bus routes. From next spring, 36 buses on routes C1 (between White City and Victoria) and 70 (between South Kensington and Acton) will become electric only.

The electric buses produce no exhaust emissions, and these two routes will be the fifth and sixth electric-only bus routes in London. But Sadiq isn't stopping there – he's promised that by 2018, TfL will stop buying diesel-only double decker buses full stop. And hey, maybe all these new initiatives will mean that London might actually last a whole week before breaching its annual air pollution limit next year.

But it's not enough to sort out London's buses – tube passengers are exposed to 'eight times more pollution than motorists'.

But on the plus side, scientists are building drones to track London's pollution levels.