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".

"Most of the victims were instantly killed by the wall's stones," he said.

Heavy rains also fell in Guangdong, Hunan, Jiangxi, Fujian, Zhejiang, and Jilin provinces, as well as the Guangxi Zhuang and the Inner Mongolia autonomous regions, according to China's meteorological authority.

The center said rainfall in southern China will be slightly reduced on Monday, but more rain will sweep across the country on Tuesday.

Shenzhen, Guangdong province, was hit on Sunday by its heaviest rainfall since 2008, with some parts receiving 276.5 millimeters of rain, according to the city meteorological department.

The city government has asked all schools to suspend classes and for employers to allow their employees to stay at home or in safe quarters.

By 4 pm on Sunday, 48 flights had been canceled at Shenzhen airport.

At Guangzhou Baiyun International Airport, 14 flights were canceled and 23 flights were delayed for more than one hour by 5:30 pm on Sunday, Hu Fang, the airport's publicity staff member, told China Daily.

Taishan of Jiangmen city was one of the most affected areas in the province. By 8 pm on Saturday, 43 villages were flooded and 17,040 people were affected, according to Jiangmen Daily. The flood in Chixi town of Taishan was once as high as 1 meter high, coming up to a person's waist.

Kunming, Yunnan province, recently invested 52 million yuan ($8.3 million) into flood control and emergency projects to prevent flooding. The projects are expected to be completed by May 31.

Last year, rain in the city seriously disrupted traffic, submerging cars and rendering hundreds of inundated buses useless.

Xu Jingxi in Guangzhou, Hu Qing in Qingdao, Huo Yan in Nanning and Yang Jun in Guiyang contributed to this story.

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