LONDON, Sept. 6 (Xinhua) -- London Mayor Sadiq Khan has announced the British capital now has the largest fleet of electric buses in Europe.

The number of electric buses on London routes has now passed 200, said Khan as he announced more are on the way for the capital.

Two of the busiest routes in London will in the next few weeks become the first in Britain to exclusively operate only electric double deck buses.

One of the routes, number 43, travels through the City of London and terminates near London Bridge.

A City Hall spokesperson said: "London currently has more than 200 electric buses, making it Europe's largest electric bus fleet, and this will grow significantly next year as Transport for London (TfL) has awarded contracts to operators for a further 78 electric double-deck buses."

The mayor, who believes the new buses are vital in cleaning London's air, said "London's toxic air is a shameful health crisis which is causing premature deaths and stunting the growth of children's lungs. As part of our work to tackle the harmful emissions we breathe and to help tackle the climate emergency, we now have the first two routes which will exclusively use electric double deck buses."

According to the mayor, this is part of a 300 million-pound plan to transform London's entire bus fleet, which is set to reduce bus NOx emissions London-wide by an average of 90 percent by October 2020.

Khan said half of Britain's roads which exceed toxic emission legal limits are in London.

Gareth Powell, TfL's managing director for Surface Transport, said: "These new buses mark a major moment on the road to a fully zero-emission fleet."

He said low emission bus zones have resulted in Londoners breathing significantly cleaner air in parts of the city most blighted by the scourge of filthy fumes.

"Next year all 9,000 buses in London will be contributing to cleaner air," he added.