Sadiq Khan has bolstered the number of electric bus routes in the capital, amid plans to crack down on London's air pollution problem.
The London mayor said next spring, 36 buses on routes C1 and 70, which run between White City and Victoria and between South Kensington and Acton respectively, will become electric only.
That will take the total number of electric buses to 121 on top of the 2,000 hybrid electric buses.
The two routes will be the fifth and sixth to become electric-only in London, following the conversion of routes 312, 507, 521 and 360 (which will be converted by the year's end).
Khan said: “More than half of London's toxic air pollution is caused by road transport, and our oldest buses are one of the biggest contributors to harmful NOx emissions in central London.
"These new electric buses will eradicate harmful emissions and will have a significant impact on the quality of our air. And this is only the beginning – by 2018 we will stop buying diesel-only double-deck buses completely."
I want London to become a world leader in hydrogen and electric bus technology and I hope other cities around the world will join me in sending the message that only the cleanest technologies are welcome where we live and work.
The capital currently has the largest electric bus fleet in Europe, and Transport for London (TfL) has also been exploring the introduction of hydrogen buses.
Khan unveiled London's first double-decker hydrogen bus at the end of last year, as part of a commitment to phase out diesel buses.
There are eight zero emission hydrogen buses operating on route RV1 – Covent Garden to Tower Gateway, while TfL is trialling charging technology enabling diesel-electric hybrid buses to charge their batteries wirelessly while they wait at bus terminals.
The mayor has set a goal of making more than 3,100 double-decker buses operating in London to be hybrids by 2019.