is about . The Ujh River is another major tributary of the Ravi River. Its source is in the Kailash mountains at an elevation of , close to the Bhaderwah Mountains in Jammu district. After flowing for , it joins Ravi at Nainkot in Pakistan. As the Ravi flows past Lahore in Pakistan ( below Amritsar in India) it is called "The river of Lahore" since that city is on its eastern bank. After passing through Lahore the river takes a turn at Kamalia and then debouches into the Chenab River, south of the town of Ahmadpur Sial. On its western bank is the town of Shahdara Bagh with the Tomb of Jahangir and the Tomb of Noor Jahan. Change of river course According to satellite imagery studies carried out over a period of 20 years (between 1972–1973 and 1991–1993), the river coursing along the India–Pakistan border meanders substantially in the alluvial plains of the Amritsar, Pathankot, and Gurdaspur districts of Punjab. This has resulted in successive damage in India as a result of the river changing its course towards India. The reason attributed to this change in the course of the river is massive river training structures/bunds constructed by Pakistan in its part of the river, close to the old course of the river. The shift in the course of the river is reported to be towards India. River water pollution In the transboundary Ravi River flowing from India to Pakistan, in urban areas of Lahore the pollution levels in the river discharge are reportedly very high, which is attributed to careless disposal of large amount of industrial and agricultural wastewater and faulty drainage systems in both countries. A stretch of the Ravi River from Lahore Siphon to Baloki headworks indicates heavy contamination of the water and sediment with Cd, Cr, Pt, and Cu. The river sediments are highly contaminated and have become a secondary source for pollution of the river water, even though some control over unauthorised discharges into the river have been checked. Hence, measures to check metal re-mobilization from sediments into the river flows need attention. The worst affected drainage is the Hadharaam drain, a tributary of the Ravi River. It is also a trans-border problem involving both India and Pakistan. A UNDP funded special programme was launched in 2006 to address the issue in both countries. Vegetation The Ravi valley in its upper reaches has