Some 50,000 delegates, including 400 from the United Nations, are to attend the event, which started yesterday in Rio. Celebrating 20 years since the Earth Summit in Rio, it’s the first time the United Nations has had a shuttle fleet entirely composed of electric vehicles.

Kathleen Abdalla, chief of the event’s organization and logistics at the United Nations Department of Economic and Social Affairs, said: ‘One important subject of Rio+20 is the sustainable city, and zero-emission vehicles can be an integral part ensuring quality of life in urban areas.

‘We are glad to have zero-emission vehicles added to our fleet. In this way, we can see and demonstrate how EVs can reduce noise pollution and eliminate tailpipe emissions. In Brazil, where most electricity is generated from renewable and local sources, electric vehicles are an excellent low carbon transport option.’

The fleet will be made up of Renault Kangoo Z.E. vans, Fluence Z.E. saloons and the Nissan LEAF, which recently began a taxi pilot programme in Sao Paulo, Brazil.