The Thai government must suspend plans to buy electricity from a dam in Lao, conservationists said Friday, as water levels along the kingdom's section of Mekong river plummet to near-record lows.The Thai-built Xayaburi dam, a few hours from the northern Lao town of Luang Prabang, is set to be completed in October, the latest in a welter of barriers across the waterway.It has been cloaked in controversy since construction began in 2012, with environmentalists raising alarm about its likel