Personally I’d argue that light pollution is a climate issue. I’m not a scientist though so maybe there’s a more precise definition here that I’m overlooking?
But regardless, energy savings was also one of the cited reasons. So to answer your question: both.
Why would you say it's a climate issue?
Because light is an environmental property to a region and one that can affect the habitat of organisms which live there.
It’s not really any difference to other traditional climate concerns like wind nor rain aside from light being a non-tactile property. But then neither is heat.
I will concede that my interpretation of the term “climate” here might not be correct. I’m not an expert in this field so it’s entirely possible I’ve stretched the definition
Climate is long-term weather patterns.
Ahhh thank you. That explains the puzzled responses to my comments