With China's biggest freshwater lake reduced to just 25 per cent of its usual size by a severe drought, work crews are digging trenches to keep water flowing to one of the country's key rice-growing regions. The dramatic decline of Poyang Lake in the landlocked southeastern province of Jiangxi had otherwise cut off irrigation channels to nearby farmlands. The crews, using excavators to dig trenches, only work after dark because of the extreme daytime heat, the official Xinhua News Agency reported.