Mainland environmentalists are mourning the sudden death of a young activist who was instrumental in the fight against a series of controversial dams in southwestern China. Xiao Liangzhong , 32, a scholar at the Chinese Academy of Social Sciences, died of a heart attack in his sleep eight days ago. His wife, Ma Qian , was by his side. 'He was a voice for the people of the region. His death will definitely be a loss,' said an environmentalist based in Xiao's native Yunnan province who had worked with him. He said Xiao's death had come as a complete shock, since he was known to be in good health. A member of the Bai minority group, Xiao had co-ordinated a nationwide campaign to stop the building of eight dams on the upper reaches of the Yangtze River in Yunnan. One of the scheme's key backers is the Huaneng Power Corporation headed by Li Xiaopeng , the son of former premier Li Peng . The dams were to be built in, above and downstream of the river's famed Tiger Leaping Gorge in Xiao's home county of Zhongdian. If completed, the dams would have forced the relocation of the region's 90,000 people, most of them poor farmers from ethnic minorities. Xiao statred his crusade against the dams project nearly a year ago, moved by the plight of his family and friends. He set out to educate environmentalists and journalists about the potential costs of the project, especially its impact on the minority peoples and their culture. For months, he organised a series of forums and led or arranged tours to Zhongdian county. His efforts paid off in September when mainland media revealed that work on one dam site had started without central government approval. The reports sparked a State Council investigation. While preliminary work at the site continues, officials in Beijing have assured the public that a thorough scientific and social assessment of the project will be done before any decision is announced. That is not expected until 2008. 'We could not have done those stories without [Xiao]. He was the force behind it,' said Liu Jianqiang , a reporter for the Southern Weekend newspaper who was one of the authors of the September article that caught the attention of senior government officials.