Diwali is celebrated on the day Lord Sriram returned to Ayodhya after completing his exile, and it also marks the day Goddess Satyabhama defeated Narakasura. Since then, it has been customary to perform Lakshmi Puja and light lamps on the evening of the new moon in the month of Ashvayuja each year. This year, the auspicious time for Lakshmi Puja is between 6:10 PM and 8:52 PM on Oct 31.