Onam is the important and most popular festival of Kerala and is celebrated each year with much fanfare all over the state during the months of August-September. It is considered as the first month of the year according to Malayalam calendar which is known as Chingam. The festival goes on from four to ten days with great joy and enthusiasm among the Malayali people. First day being called as Atham and tenth day as Thiruonam which are the most important of all.
According to the history, Onam is celebrated to welcome and honour a demon king (King Mahabali) whose spirit is said to visit Kerala at the time of Onam. During the reign of beloved king Mahabali, Kerala witnessed its golden era. The king was considered to be wise, judicious, and extremely generous and was greatly respected and worshiped by the people. The time under his reign was considered one of great prosperity and happiness. The people were living very happily with no discrimination at all. He made sure that everybody was equally treated and people get everything to live in peace.
The king Mahabali was the great grandson of Hiranyakshipu, the grandson of Prahlada and son of Virochana who came to power by defeating Gods and taking over three worlds. According to Vaishnavism mythology the defeated gods approached lord Vishnu for help in their battle with Mahabali. But Vishnu refused to help them in defeating Mahabali because Mahabali was very kind and generous ruler and his own devotee. Instead, he thought that this is a great opportunity to test Mahabali’s devotion towards him. After his victory Mahabali promised that he will grant anyone any wish while performing Yajna. So lord Vishnu appeared as a dwarf boy and made a wish for a property right over a piece of land that measures his “three steps”. Then lord Vishnu, as his fifth avatar grew bigger and covered all the land that Mahabali had conquered in just two steps. Mahabali had no land to offer him for the third step, so to keep his word, Mahabali offered his own head. Impressed with Mahabali’s act of honesty and devotion towards him, Lord Vishnu granted him a boon, by which once every year Mahabali could visit again the lands and people he previously ruled. This revisit marks the festival of Onam.