Yamuna River

It is said that, Yamuna is the consort of Lord Shri Krishna. Gokula, the divine abode of the Lord is the home of Yamuna. It is said that the river first went round Shri Krishna before descending down to earth as per the order of her Lord. River Yamuna came to be called as "Kalindi"as she touched the peak of Kalind. Then she descended down the hills and reached the plains at Khandav Vana which has been developed as Delhi city now. Yamuna and Yama are believed to be the offspring of Sun God 'Surya'. Hence it is considered that whoever takes a dip in the holy waters of the source stream of Yamuna may not have fear of death. River Yamuna, with a total length of around 1,370 kilometers (851 mi), is the largest tributary of the Ganges River Ganga in northern India. Yamuna is considered the most sacred among all the rivers as per Hindu mythology. Its source is at Yamunotri, in the Uttarakhand Himalaya, in the Himalayan Mountains. It flows through the states of Delhi, Haryana and Uttar Pradesh, before merging with the Ganges at Allahabad. The cities of Delhi, Mathura and Agra lie on its banks. Originating in the Yamunotri glacier in the Himalayas, Yamuna covers a distance of over 1,300 km, before merging with the Ganga in Allahabad.
Yamuna is one of the most polluted rivers in the world, especially around Delhi, which dumps about 57% of its waste into the river. Delhi alone contributes around 3,296 million litres per day of sewage in the river. Even the the Supreme Court Justice B.S. hauhan, sitting in a bench, headed by Chief Justice K.G. Balakrishnan could not refrain from observing that "it is no more a maili Yamuna but a ganda nullah."
Yamunotri is the source of the revered river Yamuna. It constitutes one of the four most important pilgrimages, collectively called 'Char Dham' of the Garhwal

Himalayas or Uttarakhand.