Kumbakonam is situated between two rivers Kavery and Arasalar in the southern part of Tamil Nadu, is famous for its ancient temples and for the Mahamaham Festival. It was once a capital city of Chozha Empire.
Hindus believe that taking dip at Holy rivers such as Ganga, Yamuna, Mahanathi etc would wash their sins. This was based on one of the mythological incident where once the holy rivers of India went to Brahma, the God of Creation and asked him, "How they can wash their sins while others (the earthly) leave their sins by taking dip in them?". Brahma told the holy rivers to meet near the Kumbakonam tank on the full moon day of Masi month (Tamil Month) to get rid of their (holy river's) sins. This event is referred to as "Mahamaham" and happens once in 11 or 12 years.
Masi month starts by mid February and retreats by mid March. Since Hindus believe that all holy rivers meet in Kumbakonam and the idols of all the main deities of Kumbakonam are given a dip at the tank.
Thus all Hindus like to visit this auspicious place during the Mahamaham Kumba mela to take a dip. Last time it happened was in 2004. This year(2016) it happened between February 13 to 22nd.
To commemorate this occasion India Post released a special cover. I am lucky enough to get the below cover for my collection. The cancellation depicts the star Leo and the orbit of the constellation. Hindus worship all rivers as Goddesses, so the Women Empowerment stamps fits nicely for expressing the occasion on cover.