By definition, light pollution is excessive illumination that disturbs natural activity and ecosystems at night. It is most noticeable and pervasive in larger cities, but experts believe that it is possible to lessen the impact. This does not mean plunging cities and towns into darkness, but instead to improve the efficiency of lighting systems.
Since light pollution occurs when artificial lighting brightens the sky, part of correcting light pollution involves changing the aim of artificial lighting. Even individual homeowners can aim outdoor lighting toward the ground and select motion-activated lighting, which turns off when no longer needed.
Homeowners may also choose to replace their existing lighting with low-glare fixtures, which manufacturers design specifically to reduce light pollution. Similarly, full cutoff fixtures focus light directly onto the ground and away from both the night sky and neighbors' properties. In some cases, the homeowner can even remove driveway or walkway lighting and replace them with reflectors, so as not to introduce any new light into the surrounding sky.