Lake Manasarovar is a sacred place in the Tibetan plateau , where the Indus River begins its course .
Originating in the Tibetan Plateau in the vicinity of Sacred Lake Mansarovar , the river runs a course through the Ladakh region of Jammu and Kashmir in India , towards Gilgit-Baltistan and Hindukush Ranges then flows in a southerly direction along the entire length of Pakistan to merge into the Arabian Sea near the port city of Karachi in Sindh .