Resentment is simmering among Thai fishing communities along the Mekong River facing a prolonged dry spell and record-low water levels.
Local residents blame China's dams upstream for disrupting fish and other marine life, causing a sharp drop in fish catches and in turn affecting their livelihoods.
Experts and Chinese officials, however, are not convinced that the problem lies with the dams.
China's assistant foreign minister told Thai Prime Minister Abhisit Vejjajiva when they met in Bangkok Monday (March 8) that its dams in Yunnan province do not have a significant impact on water levels downstream.
"China would not do anything to damage mutual interest with neighbouring countries in the Mekong," Hu Zheng-yue was quoted by the Thai media as saying.
The country is experiencing an unusually long dry spell. Some locals say they last saw rain in October last year.
This reporter spent two days visiting communities along the Mekong and talking to people there.
Summer has yet to peak, but already forests and roadsides are littered with tinder-dry teak leaves that crush into a million fragments underfoot.
Smoke from brush and forest fires - some started deliberately to clear land for cultivation - hangs like a shroud over the region and fills the river valley.
The Mekong is one of the world's longest rivers.
Beginning in the Tibetan plateau, it runs through China's Yunnan province, Burma, Laos, Thailand, Cambodia and Viet Nam.
The river has dropped to its lowest level in at least 20 years, according to residents.
Shipping between China and Thailand has literally ground to a halt - calling into question the utility of a new port being built at Chiang Saen to accommodate 500-tonne ships instead of the current maximum of 300 tonnes.
Riverbed crops continue to wither, and household taps are running dry as the water levels in wells drop.
More than a dozen communities in towns from Chiang Saen, near Thailand's northern border, to Pa Dai, where the Mekong leaves Thailand for a while to run through Laos, have been affected.
The locals say they have seen the river's water level go up or down by as much as a metre in a single day.
The erratic water levels have disrupted breeding and spawning in the Mekong, where about 70 per cent of the fish stock is migratory.
Locals told The Straits Times that their catches of fish had dropped and that large fish were now a rarity.
They also said that unexplained fluctuations in water levels had destroyed dry season crops such as chillies, vegetables and tobacco grown on the exposed portions of the river bed.
Thai senator Prasarn Marukpitak, who is the chairman of a senate sub-committee on the Mekong, said "China does not seem concerned".
While acknowledging that the Chinese need water for their own needs, he said they "should not think the river is theirs".
Niwat Roykaew, 50, the head of a conservation group based in Chiang Khong, told The Straits Times: "Governments can't solve these problems. It is the people who are the key."
Niwat, who is a teacher, is part of a growing number of activists across the four lower Mekong countries who are networking at a community level to exert pressure on their governments to demand an end to the exploitation of the Mekong.
He listed other issues that add to the problem: navigation, the use of chemical fertilisers in fields adjoining the river, the use of dynamite and electricity to catch fish, and encroachments on wetlands.
But much of his ire is directed at China - and at experts who say that the drought, not the dams, is to blame for the current situation.
China, they point out, contributes just 16 per cent of the water flow in the Mekong, while Laos contributes 35 per cent.
"Academics and experts often ignore local knowledge," Niwat said. "But for us here, we just know the dams are a major factor."
Last month, a Chiang Rai provincial official wrote to Yunnan's governor to ask that water be released to ease the shortage in the lower Mekong, Niwat said.
In his reply, the governor said he could not do so because Yunnan needed water for agriculture during the dry season.
A Thai conservationist and former senator, Tuenjai Deetes, told The Straits Times it was time for a six-party agreement on sharing the waters of the Mekong.
"There is clear evidence that development projects that do not consider trans-boundary social and environmental impacts have disastrous impacts on downstream areas," she said.
