Rising from the pure glacial meltwaters of the Himalayas, the Ganges (Gang Ma or Great Mother) flows down onto India's northern plain and heads eastward into the swamplands of Bangladesh, finally discharging a vast, 310 mile tongue of silt into the Bay of Bengal. As well as filling wells and irrigating crops to sustain the cities and villages along its banks, it is the spiritual lifeblood of India's primary religion, Hinduism. Bathing in the Ganges...