A combination of population growth, drought, desertification, water waste, and global warming is causing a serious water shortage in China that experts say could induce environmental and political crises. Officials are blaming drought for a 9.3 percent drop in the summer grain yield, and water rationing has been imposed on residents and industries in nearly 100 cities. One person was killed and dozens injured in July in the Shandong province when a revolt broke out after government workers tried to block streams coming from a reservoir. Meanwhile, three Chinese workers were killed and 30 injured on Sunday when part of a crane fell during work on the Three Gorges Dam, a controversial project to harness the Yangtze River. Activists say the dam will have devastating environmental consequences and displace a million people. Chinese officials in recent weeks have admitted that corruption problems have plagued the dam project, but insisted that the $24 billion effort will go on.