they cremate the bodies then the ashes are throwen into the ganges river. --------------- Not necessarily Ganges but any holy river. However, little children and sannyasis are buried. This is because, the souls of little children have not developed an attachment to their body and the souls of sannyasis are already detached, hence they don't have to be cremated.
Hindu consider the heat of fire to be the final purifier after water -the second purifier. When human is dead, his soul exist for some time near to his belongings. Hindus perform rituals up to 13 days further also so as to get the soul to peace. As soon as soul loose the contact with body, it also looses all the sensations and emotions attached to its existence in present life. Still an attachment to his belongings remains. This goes in tandem with the philosophy that the embodied soul casts away old and takes up new bodies as a man changes worn-out raiment for new.
According to Hindu Beliefs, when a person dies, his soul lingers around near the relatives, the body, and his materialistic possessions. They also believe that some rituals need to be performed, for the soul to break the bond with the body, and start a new life elsewhere. Often, we wonder why Hindus burn or cremate the body, instead of burying it. The answer lies in the belief, that by burning the body, the soul does not feel the physical association with the body anymore, which it could have, had the body been buried.
From An Introduction to Human Geography: The Cultural Landscape (Page 204, Section: Other Methods of Disposing of Bodies)
cremation
There are two methods that Hindus follow to dispose dead bodies. One is to burn and the other is to bury. Generally, unmarried people may be buried and the remaining may be burnt.
there are two ways. burn and buried (only sadhus and saints)
They bury them in the ground.
they dispose the bodies in the tower of silence
parsis do not burn or burry dead people.they dispose the bodies in the tower of silence where vulture come and eat their flesh.
Q; Why Hindus burnt their dead bodies?
there are two ways. burn and buried (only sadhus and saints)
The first person killed (Habeel) was not burnt. He was buried. All heavenly religions require the dead ones to be buried. The Hindus started burning dead bodies when Raja Ashoka killed about 1,00,000 people in a battle. It was found difficult to bury them.
Our bodies after death decompose and disintegrate. Hindus burn dead bodies on the fire pyre others bury them in the grave.
These were used in the Prison camps to dispose of the dead bodies and thus hide much of the evidence, making an exact body count a difficult task.
Bury them
I am not sure abt the particular caste but all Hindus never cremate the bodies of young children. The very young children (infants etc) are provided proper burial after death.