According to Mahabharata, King Parikshit’s son Janamejeya of Kuru dynasty was performing a snake sacrifice which was known as Sarpa Satra, to take vengeance for the death of his father from a snake bite by Taksaka the snake king. A sacrifical fireplace was made and he started killing all the snakes in the world with the help of learned Brahmin sages. The sacrifice was so powerful that all snakes were falling in the Yagna kunda. Taksaka has escaped from this and took protection from King Indra. Brahmins started increasing the tempo of the Mantras to drag and sacrifice Indra also. Taksaka was scared and coiled to Indra. Sacrificial Yagna was so powerful that it even dragged Indra into it. All the gods appealed to Manasadevi, who asked her son, Astika, to appeal to Janamejaya to stop the Sarpa Satra yagna. Astika impressed to Janamejaya with his Sastras and gained a boon. With this Astika requested to Janamejaya to stop the Sarpa Satra. After this Indra and Taksaka were saved. Since then this day is celebrated as Nagas festival as their life was spared on this day.
Nag Panchami is celebrated by all Hindus across the country and Nepal. It is celebrated on the 5th day of Shravan month of Hindu calendar. According to English calendar it comes in the month of July/August.
On this day snakes are worshipped with milk, flowers, lamps, sweets and sacrifices. Nag idols made of silver, wood or stone are bathed with water followed by milk and then worshipped. On this day Brahmins are fed and fast is observed. Digging earth on this day is sin, as it may kill snakes. In some places, milk along with sugar and rice pudding is offered to snakes. Rangoli of snakes is created on the floor and lotus in silver bowl is offered to snake. Outside walls and doorways are painted with images of snakes and auspious mantras are written on the walls. Women with brothers worship snakes so that their brothers are not harmed by snakes.