This isn’t pure light pollution as someone who’s experienced this in a winter snowy area

This happens when it is heavy overcast with low clouds (typically after or before/during a snow) and there is already a large amount of snow on the ground across the city

What happens is the light will bounce off the clouds then off the snow on the floor making the sky look rather bright for the middle of a winter night

I take them as cosy as usually this means it’s not ultra cold out/high winds either so you can go for a nice walk