In the southern reaches of Egypt, the city of Aswan is one of the hottest and sunniest in the world. Temperatures reach 41C in the summer and less than a millimetre of rain falls each year. Some years it doesn’t rain at all.

Aswan may be one of the world’s least rainy places, but it’s not even close to being the most water-stressed city. It nestles on the east bank of the Nile, close to the Aswan High Dam and the vast Lake Nasser, one of the largest manmade lakes in the world. With a capacity of 132 cubic km, the dam serves the irrigations needs not just of Aswan, but Egypt and neighbouring Sudan as well.