The second day of the Diwali festival, is the fourteenth day of the dark fortnight of the month of Ashvin, and is called Narak-Chaturdashi or Kali Chaudas and also known as Chhoti (-small) Diwali. This day is dedicated to the victory of Lord Krishna over the wicked demon king Narakasur.
Narkasur had fought against neighbouring kings and imprisoned 16,000 women, daughters of the Gods and saints. He had also defeated Lord Indra and taken away the magnificient kundale (earrings) from the ears of Aditi, mother of the Gods. When Lord Krishna learnt about Narakasur’s deeds, he decided to engage him in battle and liberate all the celestials.