At least 25 people were killed, including 12 who were trapped in a flooded subway in Zhengzhou, the capital of central China's Henan province, following rare torrential rains in the region.
Photos and videos posted on social media showed commuters trapped in chest-deep floodwaters on a train in the dark on a subway line in Zhengzhou city with a population of around 12 million. More than 500 people were evacuated from the subway system late on Tuesday. In all, about 200,000 people had to be relocated in the city because of the heavy rainfall.
The highest-level emergency alert notice has been issued across the province.
President Xi Jinping on Wednesday instructed authorities to deploy the PLA to rescue those stuck in inundated subways, hotels and public places. The PLA has deployed 3,000 personnel to help local authorities with flood control and evacuation efforts.
As the scale of the disaster continued to emerge and the damage ran into tens of millions of dollars, the Chinese army said it averted the collapse of the stricken Yihetan dam around an hour from Zhengzhou city.
On Wednesday morning, the PLA said blasting operations were carried out at the dam and troops had "successfully opened a new flood diversion opening", AFP reported.
"From 8pm on July 17 to 8pm on Tuesday [July 20], total precipitation of 617.1mm was recorded in Zhengzhou, close to the city's average annual precipitation of 640.8mm, said the city's meteorological bureau," Xinhua news agency reported.
The city registered 201.9mm of rainfall between 4pm and 5pm on Tuesday, a record hourly high for the Chinese mainland.
The city broke its own single-day precipitation record, hitting its highest level since Zhengzhou's weather station was established in 1951, the Xinhua report said.