Sutala Loka is one among the seven lower worlds situated in the bottom of the earth. Sutala Loka is ruled by the great king Mahabali, who is the grandson of Bhakta Prahalada. During the Treta Yuga, Mahabali had defeated Lord Indra, and began to rule the Indra Loka. Due to that, Lord Indra and other Devas complained to Lord Vishnu. Lord Vishnu took the avatar of Vamana and he was born as the son of Rishi Kashyapa and Mata Aditi.
One day, when king Mahabali was performing Yagna, Vamana had approached him and asked to donate three feet of land to him, and began to grow in a gigantic form. Since Mahabali was unable to offer his request, Vamana had pushed him to the Sutala Loka, an underworld, and also blessed him to live as a king in that Sutala Loka. Vamana also promised that after the end of the Kali Yuga, king Mahabali would become the next Indra, and would reside in the heaven and would rule over the Indra Loka in an excellent manner.
Sutala Loka appears similar to the Indra Loka, and king Mahabali is ruling it in a prosperous manner. Various divine devas had visited that place, and were astonished on seeing the beauty of that Loka. As per Ramayana, once Ravana went to Sutala Loka to conquer the great king Mahabali, and approached him. Mahabali had asked him to lift the ear ring of his great grandfather, Hiranyakashipu. But Ravana was unable to lift it. Mahabali laughed at him, and said, if you are unable to lift this, then how you could fight with me and with Lord Vishnu, and asked him to fight with him. But Ravana didn’t give any reply to him, and went to his Lanka kingdom.
King Mahabali is a noble king, and he has brought up by his grandfather Prahalada, and due to that, he contains very good qualities. It is believed that during the Onam festival, every year, he is coming to Kerala, which is believed to be his own country during the Treta Yuga. Still most of the Kerala people, irrespective of caste, creed, community and religion are giving great respect to their beloved king Mahabali, and they are putting nice kolams during the Onam festival day, in order to welcome their beloved king Mahabali to their homes, who had once given a golden rule.