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Liter of Light

Hundreds of millions of people live in informal settlements worldwide. Many of these chockablock dwellings lack windows or adequate daylight. In tropical locales interiors are often made darker by extended roofing favored for protection from rain and the hot sun. Residents often resort to kerosene, candles, or inventive wiring for light, risking health and safety in the process. Or they simply go without.

Filipino entrepreneur and activist Illac Diaz created Liter of Light to provide informal settlements with a cheap daytime lighting source that can be produced and distributed locally. The solution is Diaz’s figurative “liter of light,” a clear plastic soda bottle filled with water and bleach installed in the roof as a skylight. The water refracts the sunlight as it streams through the bottle, dispersing the rays 360 degrees, thereby illuminating the entire room. The recipients of the solar bottle bulbs, who pay about $1 for the bulb and installation, save money on electricity and cut back on the use of kerosene, candles, and other fuels that are responsible for indoor air pollution and fire hazards.

It provides initial supplies and volunteers to generate interest, but its focus is on teaching a community how to manufacture parts locally and install the solar bottle bulbs, with the end goal of creating green micro-businesses and empowering grassroot entrepreneurs at every step. Through a combination of social networking, community outreach, open-source sharing, and hands-on building, the organization has placed tens of thousands of these solar lights in informal settlements worldwide.

Liter of Light is widely distributing the technical know-how and has spread beyond Southeast Asia to over 15 countries like India, Nepal, and several others in South America and Africa to produce the solar bottle bulbs and easily repairable solar battery kits for solar reading lanterns, mobile chargers and street lights. There are small adaptations to the design along the way. “In Nepal they put a little bit of antifreeze in the water so it doesn’t expand and contract,” said Diaz. “In Africa, in the thatched houses, we tied three plastic bottles together and put a stick in between to attach them to the roof.”

In 2018, they collaborated with Peace Boat, a Japan-based NGO, to launch Voyage of Light, where 200 participants were trained in making different kinds of sustainable solar lights on a cruise, which would then be distributed among communities and local partner NGOs in over 20 ports across the southern hemisphere to promote renewable energy.

Recognised by the UN Habitat as one of the top global innovations in sustainability, Liter of Light will be presenting its work at the Dubai Expo 2021.