Noise pollution occurs when unwanted or excessive sound disrupts normal human or animal activities. The main sources of noise pollution are transportation systems, construction work, and industrial activity. Prolonged exposure to noise pollution can cause hearing loss, cardiovascular effects, sleep disturbances, and stress in humans. It can also damage animal communication and increase the risk of death by interfering with predator/prey detection. Some strategies to reduce noise pollution include planting trees, regular maintenance of vehicles and machines, soundproofing buildings, and imposing regulations on loud speakers.