According to legend, there was a time when the Asuras were too powerful for the Devas which resulted in Bali, king of the Asuras, to come into power. Thus Indra, Lord of the Devas, prayed to Lord Vishnu for a solution to make the Devas powerful. That is when Lord Vishnu advised Lord indra to form an alliance with the Asuras and then churn the ocean for the nectar of immortality.

The Devas and the Asuras began the procedure for churning the ocean. Since the ocean was too huge, an equally huge thing was needed to churn it. So they used the Mandar Parvat to churn it and placed Lord Shiva’s snake Vasuki to use it as a rope to push and pull to facilitate the churning. But the weight of the mountain was too huge and it kept sinking. That is when Lord Vishnu took the avatar of a huge tortoise (Kurma Avatar) to curb the mountain from sinking.

Once the churning began, many treasures came out of the ocean and they were equally divided among the asuras and the devas. However, one thing that came out the ocean invoked fear within everyone – Halahala. The Halahala poison was said to be the most dangerous poison and it had the power and potency to destroy the whole creation of the universe.

That is when Lord Shiva intervened. He took the poison and drank it while Goddess Parvati caught Lord Shiva’s throat and clenched it tightly so that the poison could not be swallowed down the throat. The poison settled in the throat and turned Lord Shiva’s throat blue. Lord Shiva had saved the universe. Since, Lord Shiva’s neck was of blue colour, he came to be known as Neelkantha (Neel = Blue, Kantha = Throat). It was due to Neelkantha that the churning could go on and in the end the nectar of immortality was successfully taken by the Devas who foiled the Asuras and good conquered over evil.