WHAT looked like an admittedly temporary reprieve for the swift currents and extraordinary biodiversity of the Mekong river is now over. In December the Mekong River Commission (MRC), an intergovernmental body made up of Cambodia, Laos, Thailand and Vietnam, called again for approval of a potentially devastating dam at Xayaburi in northern Laos to be withheld until more is known about its effect on the lower Mekong. Apart from high up in the gorges of south-western China, the Mekong remains undammed. But now CH. Karnchang, a Thai construction giant contracted to build a $3.8 billion dam at Xayaburi has told the Bangkok Stock Exchange that dam construction officially began on March 15th, and that 5,000 workers have just been hired.
The news has triggered an angry response from riparian neighbours. The December agreement, calling for further scientific study of the environmental impacts, included Laos. Opponents of the dam argue that the Xayaburi dam will cause immense harm to ecosystems and imperil 65m South-East Asians who rely on the Mekong, the world’s biggest inland fishery, for their sustenance.