The festival is celebrated in Kerala and marks the end of the summer monsoons. It also has another origin. Once upon a time the world was ruled by a demon king Mahabali who made the world a better place to live in than heaven. This annoyed the Gods who sent down Lord Vishnu as a dwarf and begged Mahabali for the amount of land that he could cover in three steps. Vamana(dwarf) grew in size, his two footsteps covering the heaven and world, the third being used to put his foot on Mahabali's head.
Mahabali made the absolute sacrifice of his ego. The spirit of sacrifice in us Indians is one of the foundations of our culture. ( read essay Foundations of Indian Culture.) Just before Mahabali was pushed out of this earth he was allowed to visit his people every year. Onam marks the return of Mahabali to his kingdom.
The social fabric in this beautiful state is based on the festival. The fabric is so knitted that no human being is segregated from the divine. Divinity is all pervading, everywhere and in every human being. It comes from Sacrifice. This does not mean denying yourselves the basics of life but denial of a ego centric existence, the root cause of all unhappiness. Life is to be lived and enjoyed.
Most of us live a three dimensional life i.e. the life of waking, dreaming and deep sleep experiences. Few of us are capable of living a life of divine consciousness called the fourth plane. If we can reach the fourth plane we can say the flower has blossomed and started giving its fragrance. This is the underlying logic behind Onam. "The blossoming of a flower."
Onam is celebrated to symbolize this flight to " Peak " in life i.e. life in the fourth plane. Onam is celebrated over ten days. After the monsoons Kerala is lush green with streams full of water, nature is at its best. Young children collect flowers every day for ten days prior to the main day i.e. Thiru-Onam. During this time beautiful floral decorations are made outside every house and boat races are held in Kerala. A twenty one course feast is the most important of the festival.
The Lord of Onam called Thrikakkarappan is made of mud, in a almost shapeless shape, with a square bottom, four faces and a pointed top. The four faces depict the four stages in a man's life. The ascent from the square bottom to the pointed top indicates the ascent of man from his animal tendencies to a highly spiritualistic stage through the four stages of Kaumaram ( bachelor student ), Garhastyam ( married householder ), Vanaprastham ( hermit ) and Sanyasam ( wandering enunciate).
There is great rejoicing during the festival. Farmers bring presents for their landlords and get presents for themselves. Family members get new clothes and gifts from the head of the family.
Some might argue about the futility of celebrating a festival based on Mythology. It is not the end but only the means of reaching the divine, of living an ego-less existence. The festival brings a sense of oneness amongst the people. There is happiness all around. Various Indian customs and festivals have evolved for the same reason. India is essentially an agricultural country. The Punjabis celebrate Baisakhi to mark the end of the harvest season, the Malayalees celebrate Onam to mark the end of the summer monsoons. A number of our festivals can be directly linked to agriculture whose success or failure depends on how the weather Gods behave.
1. To read more - www.onamfestival.org