One of the world's hottest cities has a plan to cool itself down

Riyadh in Saudi Arabia is launching a massive greening project. It's planting as many as 7.5 million trees and giving extra greenery to more than 500km2 of parks, gardens, valleys and verges. It will irrigate them all sustainably with a vast new water recycling network, increasing the daily volume of reused water from 90,000 m3 to more than 1 million m3.