The Yamuna, although a tributary of the Ganga, is virtually a river by itself. The river has been referred to in the ancient epic the Mahabharata besides numerous Puranas. The Yamuna is also known as Jamuna. The goddess of the river Yamuna is known as ‘Yami’. According to the Bhagavat Purana, she is the sister of Yama, the god of death. She is the daughter of the Sun (Surya) god, and his wife Sanjana. Yamuna is also connected to the religious beliefs surrounding Krishna.
The Yamuna originates less than a hundred miles east of the source of Bhagirathi from the Bundar Poonch glacier located in the district of Uttarkashi in the state of Uttarakhand. It grows from Yamunotri, in the Himalayas and flows parallel to the Ganga and a little to the south for most of its course before merging with the Ganges. The Yamuna traverses a total length of around 1370 kilometres or 851 miles before it merges.
The river flows towards the south direction through the Himalayan foothills and onto the plains of north India along the Uttar Pradesh and Haryana state border. Besides being a major tributary of river Ganges, Yamunotri is also a holy place of the Hindus. In the upper course of 200 kilometres, Yamuna draws water from several major streams namely Rishi-Ganga, Unta, Hanuman Ganga, Tons, Giri and Ashan. The combined stream flows through the Shivalik range of hills in Uttarakhand, Himachal Pradesh, and Uttar Pradesh.
The river enters into the plains at the Dak Phatthar where it is regulated through weir and diverted into a canal for hydropower generation and irrigation. The river is again diverted into Western Yamuna Canal and Eastern Yamuna Canal for irrigation from Tajewala barrage in the Yamuna Nagar district of Haryana. The river regains its water from ground water accrual and feeding canal through Somnadi (seasonal stream) just upstream of Kalanaur and traverses a length of about 1150 km through three states i.e. Haryana, Delhi and Uttar Pradesh.
Delhi is situated on the banks of river Yamuna. However, here the river is in its most polluted form. The survey of the Yamuna indicates that most of the time, in a stretch of about 500 kilometres, the river is in a bad shape, with water quality below desired level for designated use. In the dry season four distinct gradients of pollution load can be discerned in the river stretch between Wazirabad and Etawah. According to the reports of Central Pollution Control Board (CPCB), the stretch between Wazirabad and Okhla is the most heavily polluted one, carrying the massive input of wastewater from Delhi. This input has set off a progressive series of chemical and biological changes in the downstream water.
The availability of water in the Yamuna greatly varies with time and space since precipitation is confined to only three months in a year and that too varies greatly. Most of the water flows in the Yamuna, nearly eighty per cent in the monsoon months—July, August and September. Whatever water flows in non-monsoon period, during October to June, is extensively used for irrigation and drinking leaving very little or no water in the river to flow. Finally, the Yamuna joins the Ganges after running for more than a thousand kilometers, and with more than eleven tributaries at Prayagraj (the king of all confluences) also known as Prayag or Allahabad. The holy city of Allahabad is also called Triveni Sangam, literally, a three-way junction of rivers. The third river being the mythical Saraswati is supposed to be an underground river. New Delhi—the capital of India, Mathura—the birthplace of Lord Krishna, and Agra—the site of Taj Mahal, are three major historical places on the banks of river Yamuna.