December 26, 2012 -- Updated 1532 GMT (2332 HKT) Read more: Chinese court sentences drug gang to death over river murders Read more: Opinion: Mekong River dam threatens livelihoods and ecosystems December 25, 2012 -- Updated 0535 GMT (1335 HKT) When a migrant worker leaves his village, he also leaves his social benefits behind, acquiring a status compared to that of an illegal immigrant.