Onam is the harvest festival of Kerala take takes place during the end of August or the beginning of September. This festival is celebrated in the honor of the Mahabali Asura,a mythological figure.
Mahabali Asura,according to the legend,was a demon king who ruled Kerala before the birth of Lord Vishnu. Mahabali, who was performing the sacrificial rite of Viswajith Yagna or Aswamedha Yagna on the banks of Narmada River, declared that he would give anything that anyone sought from him during this Yagna. Lord Krishna took birth in form of a Vamana to Kashyapa and Aditi who were the parents of Demons and Demigods. Lord Vishnu incarnated in the form of Vamana,a dwarf,to defeat the Daityas. Vamana came to the place of Yagna and Mahabali went forth to receive the Brahmin boy with all traditional honours and gave him an eminent seat befitting the status of a holy person. Mahabali promised to give the Bramhin Boy whatever he wanted. Tha Daitya priest Brahmin Sukracharya had a vision of the future and he with his vision realised that the boy was not any ordinary boy but Lord Vishnu himself. But Mahabali never stepped back from his words. Vamana ashed for only three feet of land and the demon king promised to give him. As Mahabali granted his wish Vamana assumed his universal form and with his two footsteps he measured the whole universe including the earth,heaven and sky. Since there was no place left for third footstep of Vamana,Mahabali showed his head to keep third footstep,as to keep up his promise to Vamana. With that footstep Vamana pressed Mahabali to the earth known as Pathalam. Before pressing him to the ground Vishnu granted him a boon that he was allowed to come visit Kerala once in every year.
The most important things about Onam are the onakkodi,the new clothes worn on this day and onam sadya,a feast which is quite elaborate. The feast is served on banana leaves with atleast an array of four dishes. Traditional pickles and papadam are also served. Dessert is usually 'payasam',a sweet dish made of milk,sugar and other traditional Indian savories. Onam pookalam is the art works done by flowers on Onam season,in front of every houses in Kerala. Every day morning people clean the floor and put fresh flowers to make pookalam. The Kerala people celebrate this day as Onam to convince the Mahabali that the country is still prosperous as it used to be during his rule. At present people celebrate in their houses. All the functions include a lot of cultural programs like Bharatnatyam,Mohiniyattam and Thiruvathira kali.