Nigamodbodhaka is a very holy tīrtha (pilgrimage place) within Indraprastha. Bṛhaspati, the teacher of the devas, set it up there at the command of Bhagavān Vishṇu, when Indraprastha was made holy as the home of all holy places.

The name means the place where knowledge of the Vedas (nigama) rises (udbodha). The Padma Mahā Purāṇa says that Vedic knowledge shows itself of its own accord in one who bathes here, even without earlier study. The asura Vikaṭa regained the memory of his past births and was freed at this tīrtha. The merchant Śarabha’s journey here led to the birth of his son Śivāśarman.

How it was established

Indra held a sacrifice in the Khāṇḍava forest on the bank of the Yamunā. After it, Bhagavān Vishṇu made Indraprastha holy and commanded that all the great holy places be set up there again. Bṛhaspati set up the Nigamodbodhaka tīrtha within Indraprastha.

Its special power is that the Vedas, the nigamas, awaken of their own accord in one who bathes or lives there. Even those who do not know the Vedas gain Vedic knowledge through the power of the place. (Padma Mahā Purāṇa, Uttara Khaṇḍa, Chapter 200)

The freeing of the asura Vikaṭa

In an earlier life Vikaṭa was a brāhmaṇa who took temple wealth that belonged to Bhagavān Vishṇu, and so he fell into birth as an asura.

The merchant Śarabha was travelling towards Indraprastha and the Nigamodbodhaka. Vikaṭa stopped him on the road. As they came near the tīrtha, some of its holy water touched Vikaṭa, and at once he remembered his past lives. With the memory came sorrow and a clear sense of his pāpa (sin).

Standing at the Nigamodbodhaka, his karma was dissolved and he was freed. He rose to Vaikuṇṭha in a divine vehicle. (Padma Mahā Purāṇa, Uttara Khaṇḍa, Chapters 202–204)

Śarabha and the birth of Śivāśarman

Pārvatī told the childless merchant Śarabha to go to the Nigamodbodhaka tīrtha at Indraprastha and bathe there. By the power of the tīrtha and the grace of Pārvatī, a son was born to Śarabha. He was named Śivāśarman. (Padma Mahā Purāṇa, Uttara Khaṇḍa, Chapter 201)

Sources

Padma Mahā Purāṇa, Uttara Khaṇḍa, Chapters 201–205