Air pollution refers to the presence of foreign substances or contaminants in the air, which can negatively impact human health and the environment. These pollutants can be emitted by various sources such as vehicles, industries, power plants, construction activities, etc., and can include gases like carbon monoxide, sulfur dioxide, nitrogen oxides, particulate matter, volatile organic compounds, and other toxic substances. Air pollution can lead to respiratory problems, cardiovascular diseases, cancer, and other health issues in humans; it also affects the quality of air, water, soil, and ecosystems, leading to climate change and environmental degradation.