In India's flood plains, the people developed ingenious techniques to use the menacing floodwaters, not just to irrigate their fields but also to fertilise them and control diseases like malaria (by making use of fish in the floodwaters to eat away mosquito larvae, for instance). The nation's richest agricultural area in pre-British India, the flood plain of Bengal, had developed an extraordinary mechanism for harvesting the rich floodwaters. With agricultural production declining rapidly in once prosperous Bengal