The Indus River is a major river in South Asia. It originates in Tibet, near Lake Manasarovar, and flows south down through Western Tibet, Pakistan, and India. It flows into the Arabian sea and is the longest river in Pakistan. The Indus river starts its journey as a mountain spring which is fed by glaciers in the Himalayan mountains and flows through temperate forests, plains and arid countryside. The drainage area is over 450 000 square miles. It is the twenty-first largest river in the world. It is a major water source for the Pakistani people and contributes significantly to the Pakistani economy. It supports many industries as well as providing drinking water for the locals.