Getting in a big hurry to avoid the rush

Once a year, almost like clockwork, more than half the population of China uproots en masse to journey home or head elsewhere.

It's the greatest annual human migration the world has ever known, and perhaps understandably, it can cause quite a bit of upheaval on the country's transport networks.

This year's Spring Festival travel rush, or chunyun, has been ongoing since Feb 1 and won't be officially over until the second Monday of this month.