Kali Puja 2015 date is 11 November. Kali Puja is celebrated in honour of the goddess Kali, who is a form of Durga.
Legend behind Kali or Shyama Puja
Kali having destroyed the giants Raktabij, Shumbha, Nishwmbha, and their adherents, who had placed the gods in great jeopardy, was so overjoyed at her victory, that she danced till the earth shook to its foundation, and Shiva, at the intercession of the gods, was compelled to go to the spot to persuade her to desist. He however, found her so elated that he despaired of making any impression on her by words, and therefore adopted another expedient: he threw himself among the dead bodies of the slain, and when the goddess looking down perceived that she was dancing on her husband, was so shocked, that to express her surprise, she put out her tongue to a great length and remained motionless, and thus the earth was saved from the imminent danger to which it was exposed.
The worship takes place at night, and is always accompanied with bloody sacrifices. On the following day the image is cast into the river with the same ceremonies as are used with the image of Durga.
There are in Bengal, besides the clay images of Kali which are made annually, many permanent ones, generally of stone, which are worshipped all the year round. The principal one of these is at a village three miles south of Calcutta, and on this account called Kali Ghat.