Kali Puja is a ritualistic worship of Goddess Durga's foremost avatar, Goddess Kali. Performed on night of Kartik Amavasya in the Hindu month of Ashwin according to the Bengali calendar, Kali Puja coincides with another popular Hindu festival called Deepawali in the month of October or November; a few days after the Durga Puja celebrations. Though mostly celebrated in the states of West Bengal, Orissa, and Assam; it is celebrated in other parts of the country as well. However, it wasn't until the early 18th century that Kali Puja began to be celebrated. It's believed that Maharaja Krishnachandra of Navadvipa started the first of the ritual and then ordered everyone in his domain to follow suit. The tradition of annual Kali Puja was taken forward by his grandson Ishwarchandra and the elite class of the Bengal of that time. Soon, along with Durga Puja, Kali Puja became one of the biggest festivals to be celebrated in Bengal.
The ritual of worshipping Goddess Kali, on the night of Deepawali, is performed with much gusto and millions of devotees make themselves a part of it; in their homes, in temples and shrines, and in pandals (temporary shrines or open pavilions) that are set up at every nook and corner of the streets. In each of these places, the clay idols and images of Goddess Kali are ritualistically established. In some places, idols and images of Lord Shiva are also established, since He is believed to be the consort of Kali. The puja begins late in the night, and goes on through the night till dawn with meditation and chanting of mantras. Offerings of red hibiscus flowers, sweets, sweetmeats, and flowers are made to the Goddess. And on the night, people decorate their homes with lights and candles. Firecrackers, magic shows, and theatre also common on the Kali Puja.
On this night, even when most of the country is engulfed in worshipping Goddess Laxmi, the significance of performing Kali Puja is no less for the millions of devotees. Despite her fearful appearance, the relationship that devotes share with her is that of a loving and caring mother. She is considered a manifestation of supreme power; the deity of time and eternity. It's believed that worshipping her cuts down all impurities, consumes all inequity and the darkness within the devotees. Moreover, with her eternal blessings, all the sorrow, misfortunes, and sufferings are wiped clean. It is also believed that worshipping her destroys all evil, both, that lies inside and outside of her devotees. Daily, but specifically on the day of Kali Puja, many devotees visit the Dakshineshwar Temple and Kalighat Temple in Kolkata, and Kamakhya Temple in Assam; dedicated to Goddess Kali.