Once Indra was cursed by a sage and for redemption he did an austerity of Shiva in a cave. Shiva forgave his sins and blessed the place with His energy as Indreshwar Mahadev.
Curse on Indra
Indra was very insecure about heaven and his throne. He was arrogant and considered himself super powerful. Because of his insecurities, he was not afraid of cheating and deceiving. Trinity Gods warned him many times but he never reformed.
One day when he was roaming in a garden, he saw a sage in prayer. Arrogantly, he misbehaved with sage and ordered him to stop his useless prayer and bring water for him, the king of deities.
Sage neglected and continued his prayer. In anger, Indra killed him. Sage cursed Indra that the thing which is the source of his arrogance will get away from him and he will stay in forests and in caves.
Redemption of Indra
Indra realized his mistake. Being a deity his responsibility is to protect sages and not to kill them.
Soon Indra lost his kingdom. With heavy heart he went to Kailash and asked Shiva for mercy. Shiva told him that to lift the curse he need to get rid of his arrogance and insecurities, which is only possible through meditation and austerity.
Indra went to a cave and started praying Shiv linga. With full devotion and determination, he did a hard austerity of Shiva. With the positive spiritual powers and vibrations of OM, Indra got rid of his arrogance and insecurities. He got control over his senses and emotions.
For many years he was in penance inside the cave. When his austerity ended, he got free from the sin of killing a sage.
Mahadev appeared and blessed him with his throne of heaven. This Shiv Linga is known as Indreshwar Mahadev. Those who will pray here, will surely get rid of arrogance and gain control over senses and emotions.