Durga Puja is a celebration of the Mother Goddess, and the victory of the revered warrior Goddess Durga over the evil buffalo demon Mahishasura. Durga Puja is celebrated during the last five days of Navaratri, which is usually in late September or early October each year. The dates of the festival are determined according to the lunar calendar. This year it starts from 20th October, 2012.
The origin of public celebrations of grand Durga Puja can be traced back to the 16th century. With the ascent of the Mughals, Durga Puja became more of a status symbol in those days. Grand celebrations, gala feasts and huge fan fare was part of the very first 'Sharadiya Durgotsab' festivals organized by Raja Kangshanarayan of Taherpur and Bhabananda Mazumdar of Nadiya in 1606. Annual festival of Durga Puja soon became the most celebrated festival and as a day for merriment with friends, relatives, neighbors and acquaintances.
Durga Puja is celebrated with great pomp and show. The grandeur of the Puja turns Kolkata into a new city during the last four days of the festival beginning from Maha-Shashti (the sixth day) till the day when the idols are immersed in the rivers, lakes, and seas on the evening of Dashami. This ritual is performed based on the belief that the Mother Goddess descends to the Earth on Shashti, the sixth day of the Pooja and returns to her abode on Dashami, the tenth day of the Pooja. The tenth day is also known as Dussehra or Vijaya dasami.
Durga Puja is celebrated in West Bengal, particularly in the city of Kolkata. It's the biggest and most important occasion of the year there. Bengali communities in other locations across India celebrate Durga Puja as well. The festival is celebrated all over India but in different ways. Substantial Durga Puja festivities take place in both Mumbai and Delhi, also Durga Puja is popular in Assam, Tripura and Orissa. It is celebrated as Navaratri in western part of India, throughout the state of Gujarat and Maharashtra.