Correct Option
The correct option is (a) 1 only.
Explanation
The Indus River system is one of the largest river basins in the world. It is an antecedent drainage system that originates in the Trans-Himalayan region and cuts through the Himalayas to flow into the Arabian Sea.
Statement-wise Analysis
- Statement 1 is Correct: The Indus River rises in Tibet, near Lake Mansarowar. Specifically, its source is identified near the Bokhar Chu glacier in the Kailash Mountain range at an altitude of 4,164 meters. In Tibet, it is known as 'Singi Khamban' or Lion's mouth.
- Statement 2 is Incorrect: Upon originating in Tibet, the river flows in a north-westerly direction, not eastwards. It flows between the Ladakh and Zaskar ranges. It is the Brahmaputra (Tsangpo) that flows eastwards from the Mansarowar region.
- Statement 3 is Incorrect: The Indus enters Indian territory in the Union Territory of Ladakh (specifically near Damchok), not the state of Punjab. It flows through the Leh district in Ladakh before entering Pakistan near Chillar in the Dardistan region. While the name "Punjab" (Land of Five Rivers) is derived from the tributaries of the Indus, the main Indus river itself does not flow through the Indian state of Punjab.
Key Takeaway: The Indus originates near Lake Mansarowar in Tibet, flows northwest, enters India in Ladakh, and eventually drains into the Arabian Sea. It does not flow through the Indian state of Punjab.