It's easier to fix alien tech if you are living in an alien junkyard.
I don't know about those areas specifically, but there are many extremely poor areas of the world that are drowning in 1st world waste like plastic bottles and broken electronics.
Maybe the solution could use those "resources"
Some of this already exists, like the 20oz-bottle skylight (fill bottle with water and 2 cap fulls of bleach, drill hole in tin roof, stick bottle half-way through, and seal it somehow) The end result is a bright light that fills the area like a light bulb, and lasts pretty much forever.
If this new hydrophobic layer could be cheaply painted onto bottle plastic, it would take care of a large part of the raw material cost, especially if the hydrophobic layer could somehow also be made from whatever chemicals are in those old electronics.
It's cheaper to make lemonade if life hands you free lemons.