SAVING FROM A RAINY DAY - FINALIST
MEXICO

Communities have been harvesting rainwater for centuries, yet the process remains underused throughout the world. The energy used to pump water to Mexico City's residents would keep a city of 8 million people going, and widespread rainwater harvesting could meet 30% of the city's water needs. Many households already have cisterns, but water rarely reaches their neighbourhood, and paying for a water tanker is extremely expensive.

The Isla Urbana team have developed a simple collection and filtering system that uses mainly materials from local hardware stores and which local plumbers are being trained to install. Isla Urbana have no shortage of local need, but say their system can easily be transferred to other water-scarce cities too.