Missing the Dark: Malediction for the Environment and Human Health

Modern civilization has flourished after the invention of electricity and eclectic lights for getting illumination at night. Initially, artificial light was a blessing for the civilization and mankind. Later, artificial-light-at-night (ALAN) appears as a serious problem in our modern world. Rapid urbanization and industrialization are the major causes of light pollution. Indeed, artificial light has several benefits, but it has negative impacts on the entire living system, including humans. Nighttime light exposure disrupts circadian clock activities and deregulates many rhythmic behaviors (sleep, hormone secretion, and others). Insects, fishes, frogs, turtles, birds, nocturnal mammals (bats and rats), and humans are facing serious problems. Light pollution alters behavioral functions, physical and physiological activities, feeding and nesting behavior, migration, and reproductive functions in different animals. Shift work, night work, and lit areas in the streets and residential areas make a serious issue for human exposure and may cause several pathologies. Thus ALAN affects entire ecosystems, and the present review focuses on the effects of light pollution on the different living systems.