Onam important ten-day festival of Kerala is celebrated not in the honour of any god or saint but an asura king Bali. It falls at the close of southwest monsoon winds in the malayalam month of Chingam (August - September). The Puranic legend of Lord Vishnu in the form of Vamana (sixth incarnation of Vishnu) and King Bali is behind the celebration.

There is another legend is about King Bali, the grandson of Prahlad, who was pushed into the Patallok by Lord Vishnu in disguise of Vamana, the Brahmin dwarf. King Bali, though being the king of the demons was generous enough to let him pushed into the underworld and being sent to the netherworld by Vamana liberated Emperor Bali and thus Lord Vishnu gave him the lamp of knowledge. Honoring the great devotion and sense of sacrifice of Bali, the Lord granted him permission to visit his subjects once a year. Thus, Keralites celebrate Onam festival to commemorate the Advent of Lord Mahavishnu as Vamana Avatar and to rejoice the annual visit of Emperor Mahabali to meet his subjects.

During Onam, the feast and festive mood of the people, dressed in their best, is considered reminiscent of the prosperous and truthful life of the subjects during Bali`s reign. People wear new clothes (Vastra) during Onam. The `Vastra` also stands for heart. Thus, the significance of wearing new clothes is about making the heart new by removing all bad thoughts and feelings. In this festival, there are feasts also and people give presents to each other. In olden days, sports included Thallu (kind of boxing with open palm indigenous to kerala). At Cheruthuruthy, appreciative crowds gather on the green, where the dancers, resplendent in their brilliant costumes, re-enact the well-loved stories of the epic heroes and virtuous women. Pulikali, also known as Kaduvakali is a common sight during the Onam season.

Performers painted like tigers in bright yellow, red and black, dance to the beats of instruments like udukku and thakil. Snake-boat racing is a popular event during Onam. The Vallamkali (boat race) is one of the main attractions of Onam, and is best seen at Aranmulai and Kottayam. About a hundred oarsmen row huge and graceful odee (boats). Oars dip and flash to the rhythm of drums and cymbals in each boat. The songs are generally typical in character and concern people well known in Malabar. Above each boat gleam scarlet silk umbrellas and their number denotes the affluence of the family owning the boat. Gold coins and tassels hang from the umbrellas. In the evening, girls perform the Kaikottikkali (Thiruvathirakkali) in the open, dancing around the traditional brass lamp.

For the people of Kerala, the golden age is not Rama Rajya but Bali Rajya. During Bali`s reign there was neither flood nor drought, neither famine nor pestilence, neither theft nor murder and plenty ruled the land and men were equal.