Shoppers taking the bus to the centre of China’s scenic city of Hangzhou last weekend paid no attention to the man in the white T-shirt until he suddenly spilled a can of paint thinner, crouched down and lit it.

A surveillance camera recorded passengers trying to escape as flames filled the aisle and licked at the seats. Passing drivers doused the burning vehicle with fire extinguishers as smoke billowed through the street.

For all the horror of that summer day in Hangzhou, it was not the first such event. The month before, two high schoolers were injured wrestling a machete away from an attacker on a bus. In February, a four-month-old baby was among six killed when a jealous husband set fire to a bus in southwestern China.