Public bicycle systems are popular, but some struggle to make the numbers add up on the balance sheet, says Li Shanshan from the China Office of the Institute for Transportation and Development Policy.

"Except for Hangzhou, all bike-sharing systems in China are still 100 percent dependent on government subsidies," Li says, referring to the major challenge facing the country's public bike systems - to stay financially sustainable. "Whether at home or abroad, as a public service, a bike-sharing system requires government subsidies for construction and maintenance. But it's unrealistic to completely rely on government subsidies to keep the program running in the long term."

ITDP is an NGO and has offered practical advice for public bike-sharing programs in such countries as China, the US, Argentina and Indonesia.