It crosses into five countries: Afghanistan, China, India, Nepal and Pakistan with its river basin covering 860,000 km2. The upper Indus in the Himalayas is fed by glacier meltwater and monsoon rains. From the Punjab southward the river traverses desert and semidesert land, including the Thai and Thar deserts. West of Bahawalpur its main tributary, the Panjnad, which is formed by the junction of the Chenab and Sutlej rivers, joins the Indus.