Sage Atri and his wife Anusuya were doing penance in the forest called Kamad, situated near the Chitrakut mountain. Once it did not rain for many days. As a result people living in that area faced a severe drought.
Anusuya requested her husband to help out the people from their hardships. Sage Atri sat down to meditate. One by one, his disciples deserted him. Only Anusuya remained with him. She spent her days worshipping the Parthiva lingas and circumambulating sage Atri who was engrossed in his meditation. She had vowed not to have a single morsel of food till it rained.
All the deities became very pleased with their penance. They arrived at the place where both of them were doing penance and after giving blessings went back to their respective abodes.
Lord Shiva and river Ganges stayed there. It did not rain for fifty four years. Both sage Atri and
Anusuya continued with their respective penance.
While doing penance, sage Atri felt thirsty. He requested Anusuya to fetch some water. Anusuya went with a Kamandal, in search of water but did not find it anywhere.
Ganga appeared before her and said- “I am very pleased with you. You can demand anything from me you like.”
Anusuya demanded only a Kamandal full of water for her husband. Ganga instructed her to dig up a pit and when it was done she entered into that pit. Anusuya filled her Kamandal with the water from that pit and went back to her thirsty husband.
After quenching his thirst, Atri enquired from Anusuya as to where did she find water. Anusuya narrated the whole story. Both of them then went back to the place where Anusuya had met
Ganga. Both of them requested Ganga to stay at that very place. Ganga agreed to remain there on the condition that Anusuya donates all the virtues attained by her husband by worshipping Lord Shiva for one year.
Anusuya donated all the virtues, without any hesitation. Lord Shiva became very much pleased by their charitable tendencies. He appeared before them. After eulogizing, Atri requested lord Shiva to remain in his hermitage accompanied by Parvati. Lord Shiva agreed to do so. Ganga also stayed with them. Later on Atri performed a grand Yagya after the completion of which it rained heavily. Thus Atri ended the phase of drought by his tremendous penance.
River Mandakani flows from that same ‘Pit’ which Anusuya had dugged up. The Shivalinga, which was worshipped by Anusuya during that time later on, came to be known as Atrishwar Linga.