SHANGHAI (REUTERS) - Two dams in China's northwestern region of Inner Mongolia have collapsed after torrential rain, the Water Ministry said on Monday (July 19), highlighting the safety risks posed by ageing infrastructure during the summer flood season.

The dams, in the Inner Mongolian city of Hulunbuir, collapsed on Sunday afternoon. They had formed reservoirs with a combined water storage capacity of 46 million cubic metres, the Ministry of Water Resources said.

People living downstream were evacuated, with no casualties reported, it said.

The ministry said that on average, 87 millimetres of rain fell in Hulunbuir over the weekend and as much as 223 millimetres at the Morin Dawa monitoring station.

Extreme weather has hit several parts of the world in recent weeks, with flooding in Europe and heatwaves in North America, adding to worries about climate change.

Hulunbuir's city government said on its WeChat account that 16,660 people have been affected, with nearly 23,600 hectares of farmland submerged.

Bridges and other transport infrastructure had also been destroyed.

Footage posted on Chinese social media showed one of the dams being completely swept away by the water, inundating nearby fields.

China has more than 98,000 reservoirs used to regulate floods, generate power and facilitate shipping.

More than 80 per cent of them are four decades old or older, and some pose a safety risk, the government has acknowledged.

A lack of financial resources means that nearly a third of the total number have not had mandatory safety appraisals completed, Mr Wei Shanzhong, Deputy Water Resources Minister, told a briefing this year.