TOKYO (AP) — Organizers of the 2020 Tokyo Olympics have promised the most innovative, impeccably run and “sustainable” games ever. With just a little more than five years to go, doubts are growing whether they will deliver on the last pledge.

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

Tokyo was declared host for the 2020 Games in Sept. 2013, and “at this point, a sustainability plan has not been made, so that is cause for concern,” said Taruyuki Ohno, a former Tokyo government official who helped draft the bid.

A year after London was awarded the 2012 Games, it had a sustainability plan for energy conservation, environmentally sound construction standards, ethnical procurement of supplies, and environmentally friendly handling of the huge volumes of waste from the event, among other requirements.

Tokyo needs to specify in detail the standards it intends to meet, said Shaun McCarthy, who headed London’s effort to make those games as sustainable as possible.

“What gets measured gets done,” said McCarthy, who now runs a London-based consultancy, actionsustainability. “You need specific standards and you can translate them into contractual requirements for your supply chain.”

“What I’ve seen so far are some very general statements. That doesn’t make it happen. There needs to be the next stage of being very explicit as to what Tokyo will deliver,” he said. “That’s something that needs to be done quite urgently.”

The Olympics is at something of a crossroads as potential host cities reconsider the costs and benefits of staging such a major event. While the London Olympics was successful in many respects, there was room for improvement, McCarthy said in an interview.

The Beijing 2008 Olympics put grandeur ahead of environmental and other sustainability issues, leaving in its wake derelict, abandoned stadiums.

Organizers of the 2016 Olympics in Brazil’s Rio de Janeiro are under fire for a raft of problems, from a failure to clean up waterways, construction of an Olympic golf course inside a nature preserve and forced evictions of slum dwellers for urban renewal and roads. Delays have raised worries some venues and infrastructure won’t be ready in time.

WWF Japan and Japan Renewable Energy Foundation urged planners to make the 2020 Games as transformative for Japan’s stagnant economy as the 1964 Games were for the country’s ascent as an industrial power.

“The Olympics cannot be held without regard for the environment,” said Takejiro Sueyoshi, a former banker who is on the board of the renewable energy foundation. It was set up by Masayoshi Son, founder and CEO of telecommunications and Internet company Softbank Corp.

The decision to demolish Tokyo’s 51-year-old National Stadium and replace it with a massive, futuristic facility designed by award-winning British-Iraqi architect Zaha Hadid, raised complaints. A canoeing venue is being moved due to protests over the potential disruption to a wetland habitat on Tokyo Bay.

Japanese contractors are facing scrutiny over their use of plywood from Malaysian rainforests as molding for concrete.

But overall, one of Tokyo’s strongest selling points has been its plan to use many existing venues, in a city whose public transport and other infrastructure is generally first class.

Other options for improving the impact of the games might include setting targets for local job creation, certification requirements for sourcing of construction materials, and for other supplies such as food and equipment to be used during the games.

But for some construction, it may be too late to incorporate very ambitious sustainability standards into the contracting process, McCarthy said.

“If you try to do these things retrospectively, the price will go up,” he said. “If you put it into a competitive contractual situation from day one, the price will stay the same. They’ll just compete around a new paradigm.”