The World Health Organization reports that a do-it-yourself technique of disinfecting water with sunlight and plastic soft-drink bottles could save hundreds of thousands of lives a year.

The World Health Organization (WHO) reports that a do-it-yourself technique of disinfecting water with sunlight and plastic soft-drink bottles could save hundreds of thousands of lives a year. This process, called Solar Water Disinfection (SODIS) requires only sunlight, empty plastic soft-drink bottles and a black surface. The process is relatively simple: transparent bottles are filled with water and placed horizontally on a flat surface for approximately five hours. The heat and ultraviolet rays of the sun kill illness-causing microorganisms in polluted water.