Parts of China have been hit by “the heaviest rain in 1,000 years” – with footage showing underground train carriages filling with water.

More than 20cm of rain fell on the city of Zhengzhou, Henan province, in a single hour on Tuesday. In the recent European floods, the worst-hit areas of Germany saw 18.2cm over three days.

At least 12 people died in the floods and 100,000 were forced to flee their homes, according to China’s state news agency Xinhua.

Pictures and video from the region showed torrents of water flowing down streets, with rescuers working to evacuate people who had become trapped.

Power was cut to some parts of the city, trains were suspended, roads were closed and flights delayed.

Posts on social media showed commuters trapped in waist-deep flood water on a subway train.

One internet user wrote on social media: “The water outside the cabin was rising, and it was leaking in from the door.

“The water reached my chest.

“I was really scared, but the most terrifying thing was not the water, but the increasingly diminishing air supply in the cabin.”

Sky News Asia correspondent Tom Cheshire tweeted: “Very distressing scenes in Zhengzhou right now where there is severe flooding. People trapped in subway – some rescued but other videos appear to show dead bodies.”

Zhengzhou, the capital of Henan, has a population of more than 10 million and is located on the bank of the Yellow River – one of China‘s largest waterways.

Other cities in Henan – including Ruzhou – have also been ravaged by the waters.

The Shaolin Temple in Dengfeng had to close, and an aluminium plant in the city exploded, sending water surging into the facility.

The Longmen Grottoes – a UNESCO World Heritage site featuring buddhas etched into limestone dating back as far as 500 AD – are also threatened by the flooding.

More than 30 reservoirs in Henan have exceeded their warning levels and overnight the rainfall caused a 20-metre breach in the Yihetan dam in the city of Luoyang west of Zhengzhou.

In Zhengzhou, the flood control headquarters said the city’s Guojiazui reservoir had been breached.

From Saturday to Tuesday, 3,535 weather stations in Henan saw rainfall exceeding 5cm, of which 1,614 had levels above 10cm and 151 above 25cm.

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Speaking on state television, Chinese President Xi Jinping said: “Flood prevention efforts have become very difficult.”

Flooding is not uncommon in China during the rainy season, but the expansion of cities and conversion of agricultural land into housing has put more people closer to danger.

Forecasters are predicting the downpours to end by Thursday.