As clock ticks, Tokyo turns focus to delivering 'sustainable' 2020 Olympic Games

Organizers of the 2020 Tokyo Olympics have promised the most innovative, impeccably run and "sustainable" Games ever. With just a little over five years to go, doubts are mounting that they might not deliver on that last pledge.

On Tuesday, the World Wide Fund for Nature and others that are backing use of renewable energy, including Masato Mizuno, the sports-goods magnate who led Tokyo's bid for the games, issued a formal call for faster action.

They say Tokyo still has no sustainability plan and time is running short.

They warn the city risks losing out on a vital opportunity to showcase Japan's leading technologies and raise awareness about environmental issues such as global warming and devastation of tropical rainforests.