Onam is the biggest and most popular harvest festival celebrated in the Indian state of Kerala. Falling in the Malayali month of Chingam (August-September), the celebration of Onam lasts for 10 days. This carnival brings out the best of Keralite culture and tradition. Intricately decorated Pookalam, Onasadya, amazing Snake Boat Race and exotic Kaikottikali dance have always been the most alluring features of Onam. Kerala was a land of farmers distributed in villages and they mainly depended on rice cultivation; two or three crops of rice were cultivated in most of the places. The harvesting days of these crops were festival days for villagers. Thus Onam celebration started as this festival, according to some historians. Today, Onam symbolizes the perfect energy and enthusiasm of the season, and is celebrated with traditional zeal with visit to temples, family get-togethers, gifting each other clothes called Onakkodi and lots of merry making. However, one thing is certain that this was related to a season when agriculture produces were available in plenty.
Onam has two specific significances. First, it is the communal memory and celebration of the past. Second, it is the celebration of the harvest as it is believed that during those days the whole of Chingam (August-September) was celebrated as Onam season. The festival was the harbinger of spring, signalling the start of the harvest season. Certain temple records hint about the Onam celebrations that took place there. The oldest one available was from the temple 'Thiruvattuvai' of Thiruvalla. It relates to the period of 861 AD and elaborates on the routine practices followed there during Onam. Another one available relates to Thrikkakara Temple, of the period 1025 AD.
There also are fables that mark the origin of the festival. Mahabali Perumal, the ruler of Kerala, of the Kulasekhara Dynasty, wished that the temple festivals should hold more importance. He therefore, ordered the same to his people. Subordinate Kings from different parts, rulers of villages and ordinary people appreciated it and took this as an occasion to worship Vamana Moorthy, the deity of the temple on the Thiruvonam day. The 'Athachamayam' procession with decked up elephants and well dressed people was being held on the 'Atham' day (first of the ten days) at Thripunithura every year before Onam. It is a ritual that is still followed marking the start of worship of Vamana Moorthy. At Kozhikode, the Samoothiri Raja also used to have this starting festival. Later, King Perumal considered that it was tiresome for people to reach the temple from distant places, so he agreed on that people need not come over to the temple Thrikkakara. Instead, they could worship the Lord at their own houses. Hence, the people respected his concern for them and the ten day celebrations were taken up by most of the people throughout Kerala. This later became a part of the life for every Malayali as Onam.