In general, this covers light falling where it is not wanted or needed.
Dark-Sky Movement
This is a campaign to reduce light pollution going up into the sky at night. The advantages of reducing light pollution include an increase in the visibility of the number of stars at night, reducing the effects of electric lighting on the environment, and cutting down on energy usage. There are tests that measure how much light is sent upward by an outdoor fixture (to be covered in a future Journal), and if such a fixture emits no light upward, it is referred to as Dark Sky Friendly.