Heavy rains have wreaked havoc on transit systems and caused damage to homes in several regions of China, including Qingdao, Shandong province, where 18 people died when a wall collapsed on them.

Rains caused a wall at a recycling plant in Qingdao to collapse on an adjacent makeshift house for the plant's workers at 5:48 am on Sunday, killing 18 people and injuring three, said city authorities.

Wang Jingguo, who walked away from the incident with only finger injuries, but witnessed the death of his roommate, said the disaster came "all of a sudden".