The heavy rain across Henan, one of the most populated provinces with 94 million people, began on Saturday, with Zhengzhou being one of the hardest-hit areas. The severe downpours in the city are expected to last until Wednesday night.

About 20.2 centimeters of rainfall hit Zhengzhou in just one hour since 4 pm on Tuesday, exceeding China's record for hourly rainfall in inland areas. Also, between 6 pm on Saturday and midnight Wednesday, five weather stations in the city logged record rainfall amounts while 61.7 cm of rain had drenched Zhengzhou - almost on par with the annual average of 64.1 cm, the local meteorological bureau reported.

Around 6 pm Tuesday, floodwater plunged into a section of the tunnel of the city's subway line, trapping commuters inside in waist-high water. A total of 500 people had been evacuated, and 12 people died. All subways in the city have been suspended.