Nag Pachami is the day of snakes. Nags are worshiped this day in Nepal. Nags are snakes and Panchami means the fifth day after no-moon day.
Nags are worshiped on the fifth day following the no-moon (aushi). Hence, the day is called Nag Panchami. Aushi means no-moon day in Nepali.
There are various mythological beliefs about Nagpanchami and its celebration.
Mahabharata tells that Lord Krishna conquered Nag Kalia and put an end to his evil deeds on the day of Shrawan Panchami. People believe that is the reason why people started celebrating this panchami as Nag Panchami.
Kathmandu valley used to be a big lake. Nags became very angry when human drained the lake to make it livable. To protect themselves against the anger of Nagas, people gave nags certain areas as pilgrimage destinations, and promise to worship them on the day, returning harmony in nature. That is continued till date.
Lord Bhrama’s son Kashyap Rishi had thirteen wives namely Aditi, Dit, Kadru, Danu, Arishta, Surasa, Sauravi, Vinata, Tamra, Krodhavasa, Ida, Khasa, and Muni. Aditi gave birth to Devta, Diti to Garud, Kadroo to Nags, Danu to Daitya.
Those Nags were the rulers of Patal lok. The great eight nags are Ananta, Vashuki, Padhmanavha, Kambala, Shankhapala, Dhartarashtra, Takshaka, and Kaliya. These Nags were very powerful and worshiped.
In this day, Nepali traditionally post pictures of Nags above the doors of their homes to keep off evil spirits. They worship the nag by offering a symbol of milk (the white color liquid from the paste of rice). People keep milk for snakes near snake holes.
People make cottons garland, use cow dung and rice flour’s serpent’s from and worship it with cow’s milk, lava, barley, sesame, nuts and with some other religious items. It is believed that if Nag-Panchami is observed properly every year the Nags provide us good health wealth and blessing during our life. If Nags are angry they make us sick and no medicine can heal.
Puran says the earth is lifted by Shesh Nag on his head. Lord Vishnu is sleeping on its coil inside the Ocean. Kali Nag, Bashuki Nag, Astha Nag, Padma Nag; and the Karkot Nags are the very powerful Nags.
Scripture explains that without Nags’ help there will be no rain. So people worship Nags for the cause of water, offer prayers to Nags, and place food items such as milk and honey in their fields for Nags.
Few men wearing demon masks dance in the streets as a part of a Nag Panchami ritual.
We have our own myths and legends surrounding Nags, which lead us to celebrate Nag Panchami on a large scale.