NECESSITY IS THE MOTHER OF ALL INVENTIONS.... So the saying goes....

BBC News - Alfredo Moser: Bottle light inventor proud to be poor

P.S.
Former Pinoy actor and model turned social entrepreneur, Iliac Diaz, is behind the business (A Liter of Light) that supply and install such lights in Philippines - talk about a fruitful partnership with English billionaire, David de Rothschild hehe....

Liter Of Light

Liter of Light » David de Rothschild together with Illac Diaz, founder of My Shelter Foundation, promoted the use of plastic bottles cum solar light bulbs