Pedal power sees a revival as companies do battle with each other and with urban congestion and smog

Unlock them with an app, drop them off anywhere, and nip past lanes of stationary car traffic: the humble bicycle is seeing a revival in China as a new generation of startups help tackle urban congestion and pollution with fleets of brightly colored two wheelers.

The bike-share concept has attracted huge venture capital as fledgling firms wrestle for market share. Such has been the success of this made-in-China business model, which is using smartphones to reignite the nation's passion for cycling, companies are hatching plans to export the idea worldwide.

"We are focused on how to make the small bicycle have a big impact," said Davis Wang, CEO of Mobike, which launched last April in Shanghai and already has several hundred thousand of its silver-and-orange "smart" bikes in 13 Chinese cities.

Key rivals Mobike, Ofo and others are tapping into the sharing economy ethic behind Airbnb and ride-hailing apps such as Uber, and targeting China's 700 million mobile phone users, who increasingly use their smartphone for transactions.

Customers use the firm's app to release a bike's lock for rides costing as little as 1 yuan (15 cents) an hour. Bikes can be left anywhere for the next user.

Mobike's app also shows where idle bikes are, while both companies capture rider data they say can help in traffic planning.

"If we can persuade hundreds of thousands of people in every city to start to re-use bikes every day, then we can create a social impact for every city," Wang told AFP.