In October, London will start running on a single route, making Londoners breathe a little easier. Like all electric vehicles, the bus will have no emissions. The announcement was made at the first ever Clean Bus Summit held in London last week. At the summit, 24 cities from around the world promised to put 40,000 green buses on the roads within the next five years. London plans to convert all it's single-decker buses (around 300) to electric models, and make sure that all the 3,300 double decker buses are at least hybrid vehicles by 2020.