'I hate to stay indoors'

At 6:30 am, an alarm clock broke the quietness of the early morning in Beijing. Three men in their 30s rose reluctantly from their beds in a cramped underground room. After a quick wash, they ate a simple breakfast, soybean milk and baozi - stuffed steamed buns - outside.

An hour later, one of the men, Guo Bin, drove his electric tricycle to a warehouse where thousands of parcels and letters were stacked in piles and quickly sorted all the deliveries for the day. Two years ago, Guo spent 3,000 yuan ($495) on the tricycle and installed a steel box on the back to carry all the deliveries.

At 8:30 am, Guo drove to the University of International Business and Economics. His colleagues arrived on their tricycles and together they worked out who would deliver what.