Bangkok has declared all 50 districts of Thailand's capital a disaster zone after almost 300 mm of rain in three days, Al Jazeera reported on September 26.

Governor Chadchart Sittipunt signed the order after rain that began on the afternoon of September 24 submerged major roads, filled the city's canals and sent water into homes and shops. The designation gives local agencies the authority to act on their own.

"The rain keeps falling and we are doing our best. We are trying to pump the water out, but the water in canals are full," Chadchart said on social media. "The risk areas are those who live near canals. Every canal is now filled."

The east of the city was hit hardest, with totals nearing 300 mm in Min Buri, Khlong Sam Wa and Saphan Sung districts by the morning of September 26, the Bangkok Post reported. The capital had already taken 487 mm of rain between September 1 and September 25, against an average of 269 mm for the same period in 1991-2020.

The benchmark for any Thai flood is 2011, when floods across the country killed more than 680 people, affected more than 13mn and did THB1.43 trillion ($46.5bn at the time) of damage and losses, according to the World Bank's Thai Flood 2011 rapid assessment. Manufacturing bore about 70% of that bill after six industrial estates in Ayutthaya and Pathum Thani went under water, and the World Bank estimated the disaster cut 1.1 percentage points off GDP growth that year.

Somkid Pheuk-ngam, a 67-year-old vendor who lives beside a canal just north of central Bangkok, said she had kept her shop shut for two days. "The water keeps coming in. It's hard to go out now. It's at my waist level," she told AFP, calling the flood "worse than the 2011 flood".

In 2011 water from the north swamped the central plains; on September 26 the Chao Phraya river was running about 40 cm below its banks near Nuan Chawee Bridge, with the Chao Phraya Dam releasing 1,700 cubic metres a second. Water expert Chawalit Chantararat said prolonged rainfall was exceeding the capacity of Bangkok's drainage network, including its large drainage tunnels, The Nation reported on September 26.

City pumping stations were running at full capacity, moving 1,200 cubic metres of water a second, and the governor said the situation had stabilised, Khaosod English reported. Some 981 people were sheltering in 233 centres, 36 bedridden patients had been moved to hospital and at least 93 roads were closed.

Schools run by the Bangkok Metropolitan Administration will close on September 28, and the Office of the Civil Service Commission advised government agencies to let non-essential staff work from home on September 28-29.

The government said it would take two to three days to drain the water if the rain held off. The Department of Disaster Prevention and Mitigation warned that low pressure would sit over eastern, northeastern and central Thailand until September 27, bringing a risk of flash floods, forest runoff, mudslides and rivers bursting their banks.

Suvarnabhumi, the main international airport, was operating normally, though the tourism authority told travellers to allow an extra two to three hours, Reuters reported. The army set up shelters and field kitchens, and the MRT metro opened its park-and-ride car parks free of charge until October 2 so residents could move their cars to higher ground.

Industry Minister Varawut Silpa-archa put industrial estates on their highest flood alert on September 25, and no flooding had been reported inside the estates, Pattaya Mail reported. Bangpoo Industrial Estate in Samut Prakan has pumping capacity of 100,000 cubic metres an hour, and estates in Ayutthaya including Nakhon Luang, Bang Pa-in and Ban Wa have activated emergency plans and backup generators.

The rain has hit an economy that was already slowing. GDP growth slowed to 1.9% year on year in the second quarter as energy costs squeezed household spending, and output contracted 0.2% quarter on quarter. The National Economic and Social Development Council expects 2-2.5% growth for 2026.

The floods also arrive days before Thailand's new state disaster insurance takes effect. The cabinet approved a THB15.5bn ($464mn) scheme covering about 30mn homes against floods, windstorms and earthquakes, paying up to THB100,000 per home per incident from October 1, The Nation reported on September 17.

Bangkok's deluge adds to a disaster season across Asia in which floods in Nepal killed more than 1,250 people and a record-strength El Niño has left India's monsoon 15% below normal.