For the past several days Ly Minh Lam, a resident of Long My Town in the Mekong Delta province, has been unable to use water from the river for his family's straw mushroom garden.

He has begun to think of installing pipes to carry water from a ditch to the garden instead.

A 10-km section of the river, from the town to Long My District, has recently become dark and stinky. Dead fish could be spotted floating in places while some people in the area said their water has turned yellowish or reddish.

All this is the result of agricultural activities, Nguyen Tien Danh, chairman of the Long My Town People's Committee, said.

Authorities have ruled out the possibility that production businesses were responsible since they stopped their activities "a long time ago," he said.

Farmers have harvested over 10,000 ha of paddy during the recent rains, and the water has been contaminated by decomposing straws, he said.

The committee has instructed localities to close off storm water drains, dams and pumps to prevent more of the leakage from reaching the river, while the Long My water pumping station has switched to groundwater and other sources for local supply, he added.

This is not the first time the Cai Lon has been polluted and affected people's lives. In May last year too it had turned blackish and foul, which killed frogs, fish, shrimps, and other aquatic creatures farmed by many families, costing losses of hundreds of millions of dong (VND100 million = $4,330).

Authorities discovered that several water quality safety standards had been breached, meaning the river was polluted.

Many blamed sewage from several facilities in the area, most notably the Long My Phat sugar factory, for the pollution. The factory has since closed down.

The 60-km-long Cai Lon River originates in Long My and flows northwest through several districts before merging with the Rach Gia Bay in Kien Giang Province. It is the main source of water for Long My Town’s 6,000 families.