Short answers, pulled from the story.
The Ganges is 2,525 km long and rises in the western Himalayas in the Indian state of Uttarakhand. Its main stem begins at the town of Devprayag, where the Alaknanda and Bhagirathi rivers meet. The Bhagirathi rises at the foot of the Gangotri Glacier at Gomukh, at an elevation of 4,356 m.
The Ganges is the most sacred river to Hindus and is worshipped as the goddess Ganga. She is the consort of Brahma, Vishnu, and Shiva, and her descent from heaven, the avatarana, is told in the Ramayana, the Mahabharata, and several Puranas. Her waters are believed to remit sins and grant salvation to the dead.
Near Varanasi the levels of fecal coliform bacteria run more than 100 times the Indian government's official limit. Varanasi releases around 200 million liters of untreated sewage daily, and after the city adds 32 streams of raw sewage the concentration reaches 1.5 million fecal coliforms per 100 ml, with observed peaks of 100 million.
The Ganga Action Plan was an environmental initiative to clean up the river, with around Rs. 10 billion, roughly US$226 million, spent between 1985 and 2000. It has been described as a major failure, attributed to corruption, a lack of government care, poor technical expertise, poor environmental planning, and a lack of support from religious authorities.
The Ganges is home to about 140 fish species, 90 amphibian species, and reptiles and mammals including critically endangered species such as the gharial and the South Asian river dolphin. The Ganges river dolphin, India's national aquatic animal, numbered only about 3,000 across the Ganges and Brahmaputra catchments in a 2012 World Wildlife Fund survey.
The Ganges keeps its name from the confluence of the Bhagirathi and Alaknanda in the Himalayas to the first bifurcation near the Farakka Barrage. When the main branch enters Bangladesh it becomes the Padma, then takes in the Jamuna and the Meghna before emptying into the Bay of Bengal through the Ganges Delta.