I came across a poem with this phrase recently, and found myself ruminating not on the poem but on the ambiguity. Can't people coining new green terms come up with better phrases? I can't stop thinking about a light acid rain, or polluted rain showers, when I hear the term light pollution.
For an eloquent explanation of light pollution, read Simmons Buntin's essay. Simmons edits the delightful zine Terrain, which I have to love for combining green consciousness with poetry and essays. Though I can't love its subhead: A Journal of the Built and Natural Environments. So unpoetic. I'm married to an architect, so I've heard the term "built environment" plenty. It never improves upon acquaintance.
But Terrain is a great read. If you've gone green and are writing poetry, consider taking a look and sending something.