Onam is a Hindu harvest festival that marks the Malayali New Year and is primarily observed in the southwestern Indian state of Kerala. It is observed in the Malayali month of Chingam, which falls in August and September. Onam celebrates the brief annual return of King Mahabali, the legendary asura king of Kerala. It is also a holiday of thankfulness for the harvest. Onam , the foremost and joyously observed festival in Kerala, symbolizes both King Mahabali's annual return and reveres Lord Vishnu's Vamana avatar. Lasting for ten days, the festival instills a heightened festive spirit within the people of Kerala and is celebrated with remarkable splendor. Onam is the national festival of Kerala, celebrated for 10 days in the month of Chingam. It is believed that Mahabali, the mythical king of Kerala, visits his subjects on the day of Thiruvonam after ascending from the netherworld. Why Onam is Kerala’s biggest festival? Onam is one of the most vibrant and popular festivals of South India. It is celebrated not only in Kerala with much fervour and enthusiasm, but also by Malayalis residing anywhere in the world.