Details regarding Hells in Hinduism are found in the Puranas especially the Garuda Purana. Rauravam Hell is mainly used to punish those people who have persecuted other living beings. In the Rauravam Hell, people are bound with ropes by attendants of Yama and thrown into the hell where they are bitten by snakes.
When such people are thrown in the Rauravam Hell, people whom they had tormented or cheated on earth assume the shape of snakes.
This concept of heaven and hell in Hindu tradition is based on Puranas. Such stories and incidents in Puranas are meant to keep human beings disciplined on earth.
Upanishads state that hell and heaven are on earth and lucky are those who realize the true self and attain bliss here.