London is on the verge of feeling the full effect of the Olympic invasion, as the Games kick off on Friday, July 27. The organizers have been keen to emphasize the Games’ sustainability credentials, so we decided to have a look at it and see what is on offer.

Our favorite initiative is a program called Active Travel Programme to make sure public transport in London is ready and that visitors have access to walking and cycling routes across London and other cities hosting the Games. £10m (US$15.5m) has been invested in making improvements to over 75km (46.6 miles) of key walking and cycling routes leading to London 2012 venues in and outside London. This has the potential to be a true Olympic legacy: get people to walk and cycle, prevent emissions and improve human health. Follow the links for more information on walking and cycling around London.

The organizers have set up an energy centre producing energy for the Olympic stadium using a biomass boiler fueled with biomass. Besides, a combined Cooling Heat & Power (CCHP) plant captures the heat generated as a by-product of electricity production to make it 30 percent more energy-efficient than traditional generation.

Other sustainability highlights include the fact that 60 percent of construction materials by weight were delivered by rail or water transport. Besides, 90 percent of construction waste was diverted from landfill and was reused or recycled instead. The Olympic Stadium is said to be the most lightweight Olympic Stadium to date, thanks to a minimal use of steel. The roof truss was made out of unwanted gas pipelines, and recycled granite from King George V docks was used for the Stadium’s river banks. Besides, the Velodrome is almost 100 percent naturally ventilated. Rainwater is collected from the roof for flushing toilets and for irrigation.

The information above is the official angle. Hower, the list of corporate sponsors is not so green. One World Group recently reported that London police arrested people following a performance of a ceremony awarding gold medals to the ‘worst’ corporate sponsors of the Olympics at Trafalgar Square. The culmination of the ceremony involved green custard being poured over the heads of three company representatives of Dow Chemical, British Petroleum and mining giant Rio Tinto, which sponsor the Games.

“It’s disgraceful that the Olympic medals are provided by Rio Tinto when hey are responsible for such a string of international environmental and human rights controversies. These cannot be the most sustainable games ever when the medals have been sourced so irresponsibly,” said Richard Solly of London Mining Network. He also deemed the police action “heavyhanded” for arresting people for public theater. “The authorities are going to extreme lengths to protect the tarnished reputations of controversial Olympic sponsors like Dow, BP and Rio Tinto,” he added.

“BP is one of the least sustainable companies on the planet and has no right to pander to the public with its ironic title of London 2012 ‘Sustainability Partner’. Behind this distracting veneer the company has destroyed the Gulf of Mexico, is plunging into the highly-destructive Alberta tar sands, and is hurtling us towards catastrophic climate change. We’re glad to see BP’s crass greenwash effort recognized and appropriately rewarded,” added Emily Coats of UK Tar Sands Network.

The issue of corporate sponsorship is particularly strong in the UK, where protesters often criticize the ethics (or lack of) steaming from the acceptance of money from companies that pollute. In the wake of the BP oil spill in the Gulf of Mexico, protester took art museum Tate Modern to task for keeping BP as a corporate sponsor.