In ancient India, Indra was one of the most popular deities. It was same with the ancient Tamils of the Sangam age (2nd century B.C-to 3rd century A.D) also.
The Marudam region (area of the plains) Tamil agriculturists used to worship Indra as their Lord. Indra was considered as the god of the rains and since the farmers were dependent on rains for their crops, they used to worship Indra for rain, thunder and lightening.
There were many festivals celebrated in ancient India and references of them can be found in the ancient works like Vishnudhetrmottara Purana, and the Bhagavata Purana. This practice was prevalent in Tamil Nadu also. One such festival is known as `Indra Vizha`. The Chola kings whose port-city was Kaveripum-pattinam used to take the responsibility of this festival.
The detailed information on the celebration of `Indra Vizha` festival can be seen in the Tamil epics, the `Silappadikaram` and the `Manimekhalai`. As per the Manimekhalai, the famous sage Agastya helped the people of Kaveripumpattinam during a period of drought. He advised the Chola king Todittol Sembian to celebrate a festival for Indra to please him and then only Indra would bring rain to this city. According to the advice, the king arranged a big festival for the Lord Indra. In return, they got rain in the city and experienced the benefits of this, his successors also continued to celebrate this festival every year. This `Indra Vizha` festival generally continues for a period of twenty-eight days.
The festival usually commenced with a group beating drums and announcing to the people the start of the celebrations. The citizens of the town then cleaned the streets and roads and redecorate the city, with each house being adorned with many decorations. The officials of the kingdom would pay their respects to the king and wish him and the kingdom well. Musical performances would be held and the fire oblations offered in many temples for Siva, Vishnu and other deities. The festival ended with people bathing in the sea with the members of the family. It was generally believed that this festival was actually a prayer to Indra, and would remove the difficulties and dangers to those who celebrate it.
According to Manimckhalai, once a Chola king named Nedumkilli could not celebrate the Indra vizha festival. As a consequence to this, the wrath of the deity fell on the kingdom and the king. The sea engulfed the famous port city of Kaveripumpattinam and all the inhabitants had to suffer for this.
