With the way the traffic is in any place in China, you'd wonder the wisdom of carting a sheet of glass on the back of a tricycle.
He obviously is a worker planning to put the glass in somewhere, but he has no protection if he should be involved in an accident and the glass break.
We look at amazement at things like this here. I have seen several tricycles that seem set up to carry glass - this man had a ladder and was probably on his way to install the glass somewhere.