Yamuna

The Yamuna (Hindustani: pronounced [jamuna]) is the second-largest tributary river of the Ganga and the longest tributary in India. Originating from the Yamunotri Glacier at a height of 6,387 metres (20,955 ft) on the southwestern slopes of Banderpooch peaks of the Lower Himalaya in Uttarakhand, it travels a total length of 1,376 kilometres (855 mi) and has a drainage system of 366,223 square kilometres (141,399 sq mi), 40.2% of the entire Ganga Basin. It merges with the Ganga at Triveni Sangam, Prayagraj, which is a site of the Kumbh Mela, a Hindu festival held every 12 years.

It crosses several states: Haryana and Uttar Pradesh, passing by Uttarakhand and later Delhi, and meeting its tributaries on the way, including Tons, Chambal, its longest tributary which has its own large basin, followed by Sindh, the Betwa, and Ken. From Uttarakhand, the river flows into the state of Himachal Pradesh. After passing Paonta Sahib, Yamuna flows along the boundary of Haryana and Uttar Pradesh and after exiting Haryana it continues to flow till it merges with the river Ganga at Sangam or Prayag in Allahbad (Uttar Pradesh). It helps create the highly fertile alluvial Yamuna-Ganga Doab region between itself and the Ganga in the Indo-Gangetic plain. Nearly 57 million people depend on the Yamuna’s waters, and the river accounts for more than 70 percent of Delhi’s water supply. It has an annual flow of 97 billion cubic metres, and nearly 4 billion cubic meters are consumed every year (of which irrigation constitutes 96%). Like the Ganga, the Yamuna is highly venerated in Hinduism and worshipped as the goddess Yamuna. In Hinduism she is the daughter of the Sun Deva, Surya, and the sister of Yama, the Deva of Death, hence also known as Yami. According to popular legends, bathing in its sacred waters frees one from the torments of death.[2][3]

At the Hathni Kund Barrage, its waters are diverted into two large canals: the Western Yamuna Canal flowing towards Haryana and the Eastern Yamuna Canal towards Uttar Pradesh. Beyond that point the Yamuna is joined only by the Somb, a seasonal rivulet from Haryana, and by the highly polluted Hindon River near Noida, so that it continues only as a trickling sewage-bearing drain before joining the Chambal at Pachnada in the Etawah District of Uttar Pradesh.[4] The water of Yamuna is of “reasonably good quality” through its length from Yamunotri in the Himalayas to Wazirabad barrage in Delhi, about 375 kilometres (233 mi); below this, the discharge of wastewater through 15 drains between Wazirabad barrage and Okhla barrage renders the river severely polluted.

One official described the river as a “sewage drain” with biochemical oxygen demand (BOD) values ranging from 14 to 28 mg/l and high coliform content.[5] There are three main sources of pollution in the river: household and municipal disposal sites, soil erosion resulting from deforestation occurring to make way for agriculture, and resulting chemical wash-off from fertilizers, herbicides, and pesticides and run-off from commercial activity and industrial sites. The Yamuna from its origin at Yamunotri to Okhla barrage is called the Upper Yamuna.[6]