Bike sharing is on the verge of becoming an integral part of public transportation in cities across the globe. This system of impromptu bike renting is helping urban areas reduce automotive traffic and pollution while providing locals and tourists with a convenient, cheap and healthy means of transport. Currently, there are nearly 300 organized bike sharing programs worldwide. That number is growing - and not just in the West. In India, for example, the Ministry of Urban Development is preparing to launch a 10-city public bike scheme as part of its Mission for Sustainable Habitat". So how does bike sharing work? In most cities, visitors can purchase short-term subscriptions at bike stations themselves. Just walk up to a station's electronic kiosk, choose the duration for which you need access to the service, and swipe your credit card. With more than 50,000 bikes and 2,050 bike stations, the Chinese city of Hangzhou is home to the world's largest bike sharing program. Bike sharing is well integrated with other forms of public transport, with bike stations available near bus and water taxi stops.