Southeast Asia's Mekong River is slated to take on 11 dams, most designed to feed power to fast-growing and energy-hungry China, Vietnam and Thailand.
But the next planned dam -- in Xayaburi, Laos -- is being delayed.
Lao officials had billed the dam as a boon to its tiny economy and a source of electricity to villages getting by without power.
But environmentalists fear that the dam will harm the river relied upon by roughly 60 million people, AFP reports.
Thai, Cambodian and Vietnamese officials from the Mekong River Commission have ruled that the dam can't be built without further environmental study, according to Reuters.
The dam's critics include Secretary of State Hillary Clinton and Vietnam Vet-turned-Virginia Senator Jim Webb.
Global Post's own report on Laos' rush to erect dams is here.