Ganga also was known as the Ganges is one of the most sacred rivers of the Hindu mythology. She is worshipped by Hindu’s who believe that bathing in the river causes remission of sins and facilitates moksha.
Ganga came into prominence with the arrival of the Puranas. River Sarasvati was considered as one of the most sacred rivers in the Vedic literature but with the commencement of the Puranic literature Sarasvati was rarely associated with the river and emerged as an independent goddess of wisdom, learning, music, and arts.
The first occurrence of the river came in the Bhaghvata Purana, as per the text Lord Vishnu in his incarnation as Vamana appeared in the sacrificial arena of the Asura King Mahabali, then to measure the universe he extended his left foot and pierced a hole in the ground through his toenail. Through this hole, the pure water of the casual divine ocean entered the universe in the form of River Ganges and she settled in Brahma Lok the abode of Lord Brahma. In other legends, Himavat who is the personification for the Himalayan mountains and is referred to as the king of the Himalaya Kingdom is said to have fathered Ganga and Parvati with his wife and queen consort Minavati who is the daughter of Mount Meru.
The descent of Ganga on Earth is mentioned in the story of King Sagara who was an eminent King of the Suryavanshi dynasty in the Sat Yuga. King Sagara performed the Ashvamedha Yagna to prove his supremacy, this caused Indra to be fearful of the outcome of the Yagna once it gets completed. The horse was one of the most integral parts of the Ashvamedha Yagna and Indra decided to steal it and leaves it in the ashram or hermitage of the meditating Sage Kapila.
Sagara sent his sons to look for the horse and they found it in the ashram of the sage and in anger hurled insults at him which caused a disturbance in his penance when the sage opened his eyes after several years of meditation with his glance all the sons of Sagara were burned to ashes.
Since the last rites of Sagara’s sons were not performed they could not attain moksha thus Amshuman who was the grandson of Sagara performed penances and prayed to Lord Brahma to send Ganga on Earth till the end of his life, after his death his son Dilipa did the same but he too was unable to succeed finally Bhagirath who was the son of Dilipa vowed to bring Ganga down to earth so that her holy water could cleanse the souls of his ancestors and help them attain moksha and go to heaven.
Bhagirath performed various penances and finally succeeds in requesting Brahma to send Ganga on Earth and the netherworld where the souls of his ancestors were trapped and release them from their hardships. Ganga was not pleased with this decision and decided to use her full force to descend on Earth and cause destruction, when Bhagirath gets aware of this he along with Lord Brahma requests Lord Shiva to help them thus Shiva asks Ganga to first fall on his head and Ganga does so with her full might but Shiva calmly traps her in his hair and breaks the force of her descent. He ties his hair up and lets one strand of hair out through which the river flows calmly, he further lets her out in streams so that the river remains on Earth and is helpful in liberating the people of Earth from their sins. Ganga is the only river that flows through all the three worlds Swarga, Prithvi and Patal Lok that is Heaven, Earth, and Hell and it is due to this that she is also given as the name of Tripathaga in Sanskrit.
Ganga is considered as the consort of all three major deities of Hinduism as Brahma’s consort she is always with him in the form of water in his Kamandalu (Water Pot), as Vishnu’s consort she arises from his foot as mentioned in the Avatarna or the origination story mentioned in the Bhaghvata Purana, she is known as Vishnupadi.
The relationship between Shiva and Ganga is more of perpetuity and intimate one, Shiva is known as Gangadhara (bearer of Ganga) and is also known as Uma Ganga Patiswara which means Husband and Lord of Uma (Parvati) and Ganga. Metaphorically Ganga is a form of Shakti or the moving and restless energy which depicts how life on Earth is always moving forward and is never at the same place.
She is also referred to as the mother goddess as per the Skanda Purana Ganga is the foster mother of Karthikeya who was the son of Lord Shiva and Parvati. In the Mahabharata, the Vasus (the eight elemental deities) on being cursed by Rishi Vashistha to be born on Earth as human request Ganga to become their mother. Thus, Ganga incarnated on Earth and became the wife of King Shantanu of Hastinapur and she marries him on a condition that at no stage in their married life will he question her actions otherwise she would leave him and never return. Seven vasus are reincarnated on Earth and are born to Ganga and she drowns each one of them to free them from their curse but when the eighth child is born the king questions her thus the eighth son who was Dyaus or the sky god reincarnated remains alive and is compelled to live on Earth in the mortal form and is later known as Bhishma (Devratta) who is one of the most revered characters of the epic Mahabharata. Thus, Ganga which originates from the foot of Vishnu, forced to leave her abode in Brahma Lok, trapped in the locks of mighty Shiva and reincarnates in human form to relieve cursed Vasus attains the stature of a sacred river that is considered as the life-giving mother that helps the sinners cleanse their sins and all the others to attain moksha thus being an essential part of the very existence of the descendants of this land.