Historically, the origin the festival can be traced back to the ancient India, when it was probably an important harvest festival. There are various origins attributed to Diwali or Deepawali. Some hold that it celebrates the marriage of Goddess Lakshmi with Lord Vishnu. Lord Ganesha, the elephant-headed God —symbol of auspiciousness and wisdom, is also worshiped in most Hindu homes on this day.
In Jainism, Deepawali has an added significance to the great event of Lord Mahavira attaining the eternal bliss of nirvana. In Bengal, the festival is dedicated to the worship of Kali. Also on this day, Lord Krishna killed the demon Narakasura.
In South India, people take an oil bath in the morning regarded as purifying in the holy Ganga and wear new clothes. They partake of sweetmeats and light fireworks, which are regarded as the effigies of Narakasura who was killed on this day. Diwali also commemorates the return of Lord Rama along with Sita and Lakshman from their 14-year exile and vanquishing the demon-king Ravana.
In joyous celebration of the return of their king, the people of Ayodhya, the capital of Rama, illuminated the kingdom with diyas (oil lamps) and burst crackers.