We need artificial light in our daily lives, but we can have too much of it. Light pollution might be defined as excess artificial light, in the wrong place at the wrong time. Awareness of the problem, in Australia and elsewhere, has been growing since the previous edition of this Note. Building design professionals have an important role to play in tackling light pollution but, sometimes, see light pollution simply in terms of nuisance or aesthetics. This Note seeks to raise designers' awareness of light pollution as a broader issue, by exploring the biological, ecological and functional effects, as well as nuisance and aesthetics. The Note also looks at what contributions can be made by designers and others in solving the problem. Refereed/Peer-reviewed