Around 25,000 low-income homes in the Philippines have been lit up after the launch of a scheme to fit sunlight-powered "bulbs" made from old plastic bottles.
The scheme uses plastic bottles filled with a solution of bleached water, installed into holes made in shanty towns' corrugated iron roofs, which then refracts the equivalent of 55W of sunlight into the room -- during the day, at least.
It takes five minutes to make, and using a hammer, rivet, metal sheets, sandpaper and epoxy, it costs $1 to produce.