Torrential rain in the megacity of Chongqing in southwestern China triggered mudslides and flooding that killed at least six people and caused widespread disruption, Chinese state media reported.

Extreme rainfall has hit southern, central and eastern parts of China in a flood season that started earlier than usual this year.

Torrential rain since Wednesday has pelted Chongqing, which has a population of over 32 million, more than the capital Beijing, making it one of China’s most densely-populated cities.

Two drowned and four died from landslides and other flood-related events, state broadcaster CCTV said, as floodwaters rose to as high as two metres in some areas.

A meteorological station in Dianjiang county, within Chongqing, measured 254.6 millimetres (10.02 inches) of rainfall from 10 p.m. Wednesday to 7 a.m. Thursday, the highest daily precipitation on record for the county.

Such severe flooding calls into question whether China’s “sponge city” initiative launched in 2015 is effective.

The initiative aims to boost flood resilience in major cities and make better use of rainwater through architectural, engineering and infrastructural tweaks.

A video posted by CCTV showed floodwaters gushing down roads, residential areas swamped and rescuers saving residents in chest-high waters.

The deluge also disrupted transportation. Chongqing’s railway station suspended 26 passenger lines on Thursday.

China’s weather bureau said last week the country faced more frequent and unpredictable heavy rain as a result of climate change, further testing its capability to cope with extreme weather events.

Government departments have allocated 4.17 billion yuan ($573.49 million) so far this year to disaster relief, according to a Reuters tally.

China’s top legislature last month passed a revised law that was aimed to improve the efficacy of emergency prevention and response.

(Reuters)