Twelve passengers have died after being trapped in a flooded carriage on the Zhengzhou metro in Henan, central China.
The province was hit by a once-in-millennium rain event over the last three days, killing at least 25 people and displacing a further 200,000.
Survivors who were trapped in the subway's carriages have shared their stories on social media and have described how they had to cling onto its handrails as the space between the floor and the roof narrowed.
Footage has also been shared that shows waves of brown water filling up stations and leaking into carriages on one of the metro's seven lines.
According to state media, 500 people had to be evacuated from the network's line 5 because of the subway's flooding.
"I was scared when the water levelled with my chest," one woman wrote on Chinese social media site Weibo, in a post that has now been deleted.
"Many people started to suffer breathing difficulties. I heard a nearby passenger on her phone, giving her bank account details to her family, and I thought I should do the same.
"Many things came to mind but I found it hard to express. I only told my mum that 'I might not make it' and ended the call. I was on the edge of falling apart."
Another passenger described how the air was running out as he rushed to Shakoulu station to rescue his wife, who was trapped on line 5.
"I was crying all along on the one-hour walk to her rescue," he told Southern Weekly.
"Most people were either vomiting, having headaches, suffocated or fainted because of a lack of oxygen.
"The situation was dreadful."
Questions about the actions of the subway operators have been raised, although they claimed to have been 'well-prepared' for the intense flooding.
A safety worker at Zhengzhou metro said they spent a 'full night' pumping water out of the station but were overwhelmed by the volume of rain on Tuesday afternoon.
Efforts to save the city are well underway, with stranded locals offered refuge at shelters and cinemas. Tech companies such as Apple and ByteDance have also announced they will offer some financial support to help deal with the downfall, which is expected to worsen in the next few days.
Copy: James Aldred