Onam (ഓണം), a harvest festival, is celebrated in Kerala, a state in India. It generally falls in the months of August-September. Onam is a celebration to mark the annual return of the spirit of the mythical King Mahabali to his kingdom, and a commemoration of his benevolent rule and his sacrifice. The festivities are intended to assure the King that his people are happy and to wish him well.

Mahabali, according to the legend was a just and a wise ruler dearly loved by all his subjects. He however incurred the wrath of the gods when he tried to extend his kingdom to patalam (the nether world), and to the heavens. The ruler of heaven and king of the devas, Lord Indra, was apprehensive of Mahabali's popularity and might, and approached Lord Vishnu, the preserver in the Hindu trinity, for help and advice.

Vishnu then took on the shape of a (Vamana) Brahmin, (the Vamana is considered one of the avatars of Lord Vishnu), and went to see Mahabali. He approached the King in this form and asked him for alms. Mahabali was a very generous man. He told the Vamana to ask for anything. The Vamana asked for three paces of land and the king agreed to the request.

Immediately the Vamana began to grow in size until he became as big as the universe. With the first step, he covered the entire earth, with the next patalam , and there was no land left for his third step. Mahabali, who was a man of principles, in order to stay true to his word, asked the Vamana to step upon his head. The Vamana placed his foot on Mahabali's head and pushed him into patalam. However, before doing so, he granted Mahabali a boon. Mahabali requested to be allowed to return and country once a year to visit his people. As the legend goes, he comes to visit his people during the festival of Onam. In memory of the happy days of Mahabali’s rule, his annual home-coming is celebrated in Kerala with pomp and splendour.

The glory of those ancient times is recaptured in a popular folk song, which is sung all over Kerala:

When Mahabali ruled the land Everyone was equal Happily they lived Danger befell none There was no falsehood, or fraud And no untruth

The most important things about Onam are the onakkodi, the new dress worn on this day and ona sadhya, a feast which is quite elaborate. During Onam, people create a multi-colored floral decoration on the ground in the front of their home called a pookkalam. Young children are often entrusted with the task of gathering and laying out the flowers in elaborate patterns.

The Vallamkalli or the snake boat race is another event that is synonymous with Onam. Well-known races include the Aranmula Boat Race and the Nehru Trophy Boat Race . About 100 oarsmen row huge and graceful snake boats and men and women come from far and near to watch the snake boats skim through the water.

This festival is also important because of its secular character. It is celebrated with equal fervour by the Hindus, Muslims and Christians.