Why is the ganges river so dirty?

More than 400 million people live along the Ganges River. An estimated 60,000 persons ritually bathe daily in the river, which is considered holy by Indians. In the Hindu religion it is said to flow from the hair of the god Shiva. The spiritual and religious significance could be compared to what the Nile river meant to the ancient Egyptians. While the Ganges may be considered holy, there are some problems associated with the ecology. It is filled with chemical wastes, sewage and even the remains of human and animal corpses which carry major health risks by either direct bathing in the water ,or by drinking the highly contaminated water.