Vinayaka Chathurthi or Pillayar Chathurthi is observed with much fervour in Tamil Nadu in August or September. As per the Hindu calendar, it falls on the fourth day of Bhadrapada month. The legend behind this day says that it was on this day that Lord Shiva beheaded Lord Ganesh for refusing him entry into his abode. Lord Ganesh was guarding Lord Parvati while she was taking a bath. Later, Lord Shiva brought him back to life, by replacing his head with that of an elephant. It was Lokamanya Tilak who raised the stature of Ganesh Chathurthi to that of a national festival. He installed the clay image of Ganesh in a public place and later submerged all displayed idols in the sea. Tilak saw these celebrations as a tool to bridge the gap between upper and lower castes. In Tamil Nadu, this ritual involving the immersion of the idols is known as Ananta Chaturdashi. Devotees in the state prepare Kozhukattai, known to be the favourite sweet dish of Lord Ganesh. Rice flour dough is stuffed with jaggery and coconut. Pran Pratishtha, Shodashopachara, Uttar Puja and Ganpati Visarjan are the four rituals associated with the festival. Grand celebrations are held at the Vinayaka temples, Rock Fort Uchi Pillayar temple situated on top of the hill in Tiruchirappalli and Sri Karpaga Vinayaka Temple in Pillayarpatti in Sivaganga district.
With the advent of technology, the idols of Ganesha are seen to have moving arms and heads. Expos with the display of Ganesh idols also take place during this festival.