The programme also looks at Sheffield-based company Xeros who have developed technology using nylon polymer beads in washing machines to dramatically reduce water consumption, and Adam Shaw meets the team behind KickStart who have designed a simple irrigation tool that helps African farmers start profitable businesses.

Gideon Long reports on a method of capturing the water from fog to help ease the drought problem plaguing the desert regions of northern Chile.  

This episode of Horizons airs on Saturday, 20 June at 10:30 on BBC World News, channel 400 on DStv. It repeats on Sunday, 21 June at 16:30 and 22:30.