In the towering peaks of the Himalayas sits the lifeblood of Pakistan’s agricultural sector: huge glaciers that fill the tributaries of the Indus river and flow 1,700 miles through India into Pakistan’s vast plains and on to the Arabian Sea.

The Indus and its five tributaries supply the world’s largest contiguous system of irrigation canals and feed the fields of wheat, cotton, rice, sugar cane and oilseed that are the core of the agricultural sector, which represents a quarter of Pakistan’s economic output.