Diwali dates back to ancient times in India, as a festival after the summer harvest in the Hindu calendar month of Kartika. The festival is mentioned in Sanskrit texts such as the Padma Purana, the Skanda Purana both completed in second half of 1st millennium AD but believed to have been expanded from a core text from an earlier era. The diyas (lamps) are mentioned in Skanda Purana to symbolically represent parts of sun, the cosmic giver of light and energy to all life, who seasonally transitions in the Hindu calendar month of Kartik.
Hindus in some regions of India associate Diwali with the legend of Yama and Nachiketa on Kartika amavasya (Diwali night). The Nachiketa story about right versus wrong, true wealth versus transient wealth, knowledge versus ignorance is recorded in Katha Upanishad composed in 1st millennium BC.
The religious significance of Deepavali varies regionally within India, depending on the school of Hindu philosophy, regional, legends, and beliefs.
Hindus across the world celebrate Diwali in honor of the return of Lord Rama, his wife Sita and his brother Lakshmana from exile of 14 years after Rama defeated Ravana. To honor the return of Lord Rama, Sita and Lakshmana from Lanka and to illuminate their path, villagers light Diyas to celebrate the triumph of good over evil.For some, Diwali also celebrates the return of Pandavas after 12 years ofVanvas and one year of “Agyatavas” in Mahabharata. Furthermore, Deepavali is linked to the celebration of Lakshmi, who is venerated amongst Hindus as the goddess of wealth and prosperity and is the wife of Lord Vishnu. The 5-day festival of Diwali begins on the day Goddess Lakshmi was born from the churning of cosmic ocean of milk by the Devas (gods) and the Asuras (demons); while the night of Diwali is the day Lakshmi chose Vishnu as her husband and they were married.
Hindus in India’s eastern region, such as Odisha and West Bengal, worship the goddess Kali instead of Lakshmi, and call the festival Kali Puja. In India’s Braj and north central regions, the god Krishna is recognized. People mark Mount Govardhan, and celebrate legends about Krishna. In other regions, the feast of Govardhan Puja (or Annakoot) is celebrated, with 56 or 108 different cuisines prepared, offered to Krishna, then shared and celebrated by the local community.