A festival occurring in the Tamil month Thai (January - February), on the day of the star Poosam around Pournami (Full Moon) is celebrated as Thaipusam [Thai Poosam].
"Maha-Sivaratri" is a Hindu festival observed on the night of the fourteenth day of the dark half in the month of 'Magha', in Tamil 'Thai', corresponding to the English months 'February—March', in honour of Siva
The Lord Mahavishnu, one of the Hindu Trinity, representing the preservative aspect of the universe as in his previous incarnations (avatars), descended into the world to kill the ten-headed Asura named Ravana..