Thailand raced on Tuesday to build flood walls on the outskirts of Bangkok to prevent the worst floods in half a century from inundating parts of the capital later this week.

At least 269 people have been killed by heavy monsoon rains, floods and mudslides that have battered 27 of Thailand’s 77 provinces since late July, according to the Department of Disaster Prevention and Mitigation

Much of Thailand’s north, northeast and central plains are flooded, affecting 2.3 million people.

Bangkok only two metres above sea level could be next if water overflowing from reservoirs in the north arrives at the same time as high estuary tides are overdue.

Rescue workers hastily built a flood wall in Pathum Thani, north of Bangkok, where strong currents burst a river embankment overnight, flooding homes in water at least two metres high.

“I’ve never seen floods as bad as this year. The first floor of my house is all flooded and it’s coming up to the second floor,” said Wanpen Suanmakam, 62, a resident in Pathum Thani, a province intersected by canals that feed its rice paddies.

Another resident, Sukanna Saeieaw, 60, almost up to her neck in water, said a makeshift walkway briefly helped people avoid water when the road was flooded but it was quickly washed away.

“The water came in very fast,” she said.

Lerpong Kaewsrichan, Pathum Thani deputy governor, said the water had mostly submerged farmland but two industrial estates in the area had been spared for now.

About 2,000 people were packed into a Pathum Thani evacuation centre, most from the neighbouring province of Ayutthaya, one of the worst affected.

Nearly 198 factories in a sprawling industrial estate there, including an assembly plant of Honda Motor Co Ltd , have closed after floodwater breached a wall of sandbags at the weekend.

Nikon Corp said it has halted a digital SLR camera production site due to flooding.

Toyota Motor said it halted operations at all three Thai factories.

Thailand is a major production centre for many of the world’s biggest car manufacturers.

Their assembly plants are mostly in eastern Rayong province, which has not been badly hit, but there is bound to be disruption because car part makers elsewhere have been affected.

About 1.38 million hectares of farm land nationwide is under water about 13 times the size of Hong Kong and more then 700,000 homes were destroyed or damaged.