Nag, snake god is believed to be source of water. Nag Panchami festival is celebrated by worshipping snake god to make them happy so that they keep on sending water. It is said that in ancient times, Nagas stopped rain in Nepal . Knowing that the king made the Nagas happy by using his tantric power and Nagas started rain in Nepal . Since then, the king ordered his people to celebrate the festival Nag Panchami every year to keep Nagas happy. On this day, people stick a picture of Nag above their doorway and perform pooja and offer foods and cow milk.