Washington, D.C.’s bike sharing program has 1,100 bikes. London’s system has 6,000. And Paris has more than 20,000.

But on the other side of the globe, Hangzhou, China has them beat with more than 60,000, according to a recent report by National Geographic.

To see how it all works, check out this short from Streetfilms:

Bike shares -- where a user can pick up a bicycle at one service point, ride it, and then drop it off at another and walk away -- are growing in popularity. China, along with many other developing nations, has a long-held cultural tie to bicycling. Demand for automobiles skyrocketed in recent decades, but in a city of 6.7 million like Hangzhou, it would be impossible to build enough roads to support this, not to mention environmental concerns.

Bike shares are cheap (nearly free for many in Hangzhou), highly accessible, and part of a sustainable urban growth model. Hangzhou hopes to expand its system to 120,000 bikes by 2020 and other cities are taking notice of its success. Companies in Beijing, Rio de Janeiro, and Mexico City are making a go of it and hope to remove the training wheels soon.

Photo: World Bank Photo Collection (flickr)

Today China announced several plans to help fulfill its promise to make the Beijing Olympics a "green" event. Plans include halting construction projects, banning the use of 3.3 million vehicles, shutting down inefficient coal boilers, and cutting emissions from the heaviest polluting industries in the months leading up to the Games.

Although a well-intentioned effort, many are concerned this won't make a difference a mere four months before the Games. With China's levels of ozone and particulate matter five times higher than World Health Organization safety standards, some athletes are worried about permanently damaging their respiratory systems. The world recordholder in the marathon, Haile Gebrselassie, announced he won't run this year out of concern for his health.

The Beijing Environmental Protection Bureau, however, is not concerned. It counted 67 “blue sky days” in Beijing from January through March — the highest count in nearly a decade. China isn't clear on what this means, but as Tim Johnson, the Beijing bureau chief for McClatchey Newspapers, says “When Chinese officials talk about 'blue sky' days, they don’t mean days when the sky is really blue. They mean days when sunshine can penetrate the haze and create a shadow. The sky is still an icky gray."

China may be making a considerable effort to improve air quality during the Summer Games, but their efforts might be better spent on longer-term solutions. Many former Olympic cities used the Games as an opportunity to fix longstanding problems. But in China's case, it looks as if those 3.3 million cars will go right back on the roads.