Light pollution, also known as photopollution or luminous pollution, is excess or obtrusive light create by humans. Among other effects, and like any other form of pollution, it disrupts ecosystems, can cause adverse health effects, obscures the stars for city dwellers, and interferes with astronomical observatories. Light pollution can be construed to fall into two main branches: annoying light that intrudes on an otherwise natural or low light setting and excessive light, generally indoors, that leads to worker discomfort and adverse health effects. Since the early 1980s, a global dark-sky movement has emerged, with concerned people campaigning to reduce the amount of light pollution.