Basically, restate what you've written in your essays, but go deeper and broader. By deeper, we mean explaining in more detail those factors and motivations that you mentioned in your essays. By broader, we mean all the stuff you couldn't fit in the essays. A good answer shows both depth and breadth. If we had to pick one, we'd say to focus on.
The full moon day of the Tamil month of Thai Thaipusam is a Hindu festival celebrated mostly by the Tamil community. The word Thaipusam is derived from the Tamil month name Thai and Pusam, which refers to a star near the location of the moon during the festival; the festival commemorates the occasion when Parvati gave Murugan a spear so he could vanquish the evil demon Soorapadman.