For millions in the developing world, water can be as dangerous as it is life saving, spreading life-threatening diseases such as diarrhoea and cholera.

Every day men, women and children are forced to drink, bathe and wash clothes and utensils in fetid supplies ripe with sewage.

One such slum is Kibera, part of the Kenyan capital Nairobi – but residents there hope that a low-tech solution is at hand.

Locals now collect water from infected tanks, pour it into clear plastic bottles and then leave them on tin rooftops for at least six hours.

Laboratory tests reveal that the sun kills dangerous disease-spreading bacteria by zapping them with UV radiation and heat through a process known as solar disinfection.

An estimated two million people around the world are now using solar disinfection to draw clean water.

Is enough being done to ensure that the developing world has clean water? Are low-tech solutions losing out to higher-cost developments?

Let us know what you think and we will use some of the comments on tonight's show, when you can also watch David McKenzie’s report from Kibera.