The Ganga is mentioned in the Rig-Veda, the earliest of the Hindu scriptures. The Ganga is mentioned in the nadistuti (Rig Veda 10.75), which lists the rivers from east to west. In RV , the word Ganga is also mentioned, but it is not clear if the reference is to the river. RV says that "your ancient home, your auspicious friendship, O Heroes, your wealth is on the banks of the Jahnavi (JahnAvyAm)". This verse could possibly refer to t he Ganga. In RV , the Jahnavi and the Gangetic dolphin occur in two adjacent verses.

According to the Hindu Purans, Goddess Ganga used to exist only in Heaven. Then prince Bhagirath worshipped Ganga to descend on earth.This is why Ganga is also known as Bhagirathi. In the Mahabharath this story is also mentioned. In fact, Ganga is a major character in the Mahabharath, where she is the mother of Bhism.Another version of the myth tells us that Ganga descended to earth to purify the souls of the 60,000 sons of an ancient ruler, King Sagara, who had been burnt to ashes by an enraged ascetic.

In the Uttarakhand Himalayas where glacial water flowing from a cave at Gaumukh, is the origin of the Bhagirathi river. Gaumukh has been described as a desolate place at an altitude of about 4,000 meters (13,000 feet). Twenty-three kilometers from Gaumukh, the river reaches Gangotri, the first town on its path. Thousands of visitors come to Gangotri each year, from every part of the world. Gangotri is situated at a height of more than 10,000 feet in Uttarkashi district, is one of the four shrines of Badrinath, Kedarnath and Yamunotri commonly called Chardham. So far nearly 3.50 lakh tourists have visited the shrine this year The shrine, dedicated to Goddess Ganga, is closed in October-November every year as the area remains snow-bound during the winters.

The Kumbh Mela the largest religious gathering on earth, is held every 12 years on the banks of the Triveni Sangam - the confluence of the holy rivers Ganga, Yamuna and Saraswati. The Mela alternates between Nasik, Allahabad, Ujjain and Haridwar every three years. The one celebrated at the Holy Sangam in Allahabad is the largest and holiest of them. The Mela is attended by millions of devotees, including Sadhus. A holy dip in the sacred waters is believed to cleanse the soul.

The Ganga has been described by the World Wildlife Fund as one of the world’s top ten rivers at risk. It has over 140 fish species, 90 amphibian species, and five areas which support birds found nowhere else in the world. According to studies reported by environmental engineer D.S. Bhargava of the University of Roorkee, the Gange decomposes organic was 15 to 25 times faster than other rivers. The Ganges has an extraordinarily high rate of reaeration, the process by which it absorbs atmospheric oxygen. When organic waste is dropped into it, as much as 60 per cent of the BOD is processed within an hour. The water quality samples also suggest that the Ganges retains DO much longer than does water from other rivers.

The flora and fauna found along Ganga banks are vital to nutrient and water conservation, and control of soil erosion. 451 million people living in its basin are directly and indirectly dependent upon the Ganga. Water by the monsoons, this silt-enriched land produces a significant portion of the rice, wheat, millet, sugar, and barley needed to feed the world's second most populous nation. The rain feds the land, dilutes the river's muddy stream, flushes out excess sediment and suspended matter, and revitalizes the river where its flow was sluggish. The Ganges and its tributaries provide a perennial source of irrigation to a large area. The Ganges can swell a thousand-fold during the monsoons

The Ganga is one of the world’s most rapidly shrinking rivers, a recent study of 900 rivers in the world has found. One of India’s most culturally and economically important rivers is among 45 in the study that showed a statistically significant reduction in discharge to the ocean. In 2004, the Ganga had 20 per cent less water than it did 56 years.The Allahabad high court on January 12, 2011 asked the state government to ensure maintaining 50 per cent of water level in the river Ganga in the interest of general public.

Ganga and groundwater contamination While pollution level in the holy Ganga is becoming a grave concern for scientists of the country, threat of groundwater contamination is also looming even larger than anticipated and calling for urgent measures for its mitigation.

Today, over 29 cities, 70 towns, and thousands of villages extend along the Ganga banks. Nearly all of their sewage – over 1.3 billion liters per day - goes directly into the river, along with thousands of animal carcasses, mainly cattle. Another 260 million liters of industrial waste are added to this by hundreds of factories along the rivers banks. Municipal sewage constitutes 80 per cent by volume of the total waste dumped into the Ganga, and industries contribute about 15 percent. The majority of the Ganga pollution is organic waste, sewage, trash, food, and human and animal remains. Over the past century, city populations along the Ganga have grown at a tremendous rate, while waste-control infrastructure has remained relatively unchanged

The Ganga is also one of the rivers most threatened by climate change. According to a report by the Intergovernmental Panel on Climate Change looking at the threat from climate change to human development and the environment, “only the polar icecaps hold more fresh water than the Himalayan glaciers”: “If the current trends of climate change continue, by 2030 the size of the glaciers could be reduced by as much as 80 per cent,” warns the report, titled “Up in Smoke – Asia and the Pacific”, released here in November 2007.

On September 22, 2008 Prime Minister Manmohan Singh has assured giving river Ganga a national heritage status, a statement by the Hardwar-based Ganga Raksha Manch said. The prime minister pledged to revive the glory of the river and look into the issue of pollution in the river along its stretch from upper reaches in Hardwar to Ganga Sagar in the Bay of Bengal

After two Ganga Action Plans failed to deliver the goods, seven major IITs of the country have joined hands to find ways to clean up the national river. After perusing a report submitted by the seven IITs, namely IIT Kanpur, Mumbai, Guwahati, Delhi, Kharagpur, Chennai and Roorkee, the Union Ministry of Environment and Forests has asked them June 10, 2010 to prepare a work plan for National Ganga River Basin Authority in the next 18 months. The Cabinet Committee on Economic Affairs (CCEA) on June 10, 2010 approved a proposal for carrying out the second phase of Ganga Action Plan worth Rs crore with Japanese assistance at Varanasi.

The Ganga Action Plan was initiated by the late Prime Minster Indira Gandhi, who called for a comprehensive survey of the situation in In 1985, the government of India launched the Ganga Action Plan, which was devised to clean up the river in selected areas by installing sewage treatment plants and threatening fines and litigation against industries that pollute. The 2006 official audit of the Ganga Action Plan has revealed that it has met only 39 per cent of its sewage treatment target. Moreover, the plan is behind schedule by over 13 years. According to the legal counsel, Central Pollution Control Board, Mr Vijay Panjawani, even after spending Rs 24,000 crore, the Ganga remains as dirty as ever.