Onam is one of the major festivals of Malayali people and this festival is celebrated with great enthusiasm by almost all Malayalees living in India and abroad. Although Onam is the grandest event organized in Kerala, but this festival is celebrated with much fanfare in many other states as well. In the year 2020 Onam festival will begin on Saturday, 22 August and ends on Wednesday, 2 September.

People in Kerala start preparations for this festival ten days in advance. During this time, people clean their houses. People celebrating Onam make beautiful Rangolis with flower petals in the courtyard of their homes on this day, in the local language these Rangolis are called 'Pookalam'.

Along with this, people also place the idol of King Mahabali in their homes because people believe that during the festival of Onam, King Bali comes back to earth from the Patal–Lok (abyss) to meet his subjects. This idol of King Bali is placed in the center of Pookalam with the idol of Vamana avatar of Lord Vishnu.

The floral decoration works for eight days and on the ninth day every house is worshiped by making an idol of Lord Vishnu. On this day, women play applause, dancing and singing all around it while worshiping Vishnu. At night, idols of Ganesha and Shravan Devta are made. After this, the children sing songs dedicated to Vamana avatar. The lamps are lit in front of the idols, the idols are immersed on the tenth day after the worship.

On this day, along with celebrations, dances like Kathakali dance, Kumattikali (mask dance), Pulikali dance (dance performed in lion costume) etc. are organized to entertain the people. Along with this, boat races and different types of sports are also organized on this day.

In Kerala, tea, ginger, cardamom, black pepper and paddy crops are ready to harvest these days and people celebrate this festival in the joy of good harvest. In the city, this festival is celebrated with enthusiasm by all the community. Onam is celebrated at the start of 'Chingam', the 1st month of the Malayalam calendar. This festival lasts for 10 days, with the 1st and 10th days being the most important.

Onam in Puranas: Onam festival is associated with Emperor Mahabali. This festival is celebrated in his honor. People believe that Vamana, the 5th incarnation of Lord Vishnu, appeared in the kingdom of Emperor Mahabali on this day of Chingam month and sent him to Patal-Lok. He is believed to come once a year to see his peoples. Since then, the festival of Onam is celebrated every year in Kerala to honor King Mahabali.