People prepare sweet Pongal, made of jaggery with rice and milk, in traditional mud pot or in brass cookware, with ginger tied on the top, and offer prayers to Sun God, along with a piece of sugarcane.
The food is shared with relatives and neighbours after being offered to lord Sun.
Cows and bulls would be worshipped, particularly in the southern districts of the state, for 'Mattu Pongal' tomorrow, while people visit relatives on the last day 'Kaanum Pongal'.
For the 'Kannum Pongal' festival, security has been beefed up at several places, including at the Marina beach Chennai, where people throng in very large numbers.
Governor K Rosaiah, Chief Minister Jayalalithaa, DMK President M Karunanidhi and other leaders have extended greetings to the people.