This document discusses air and water pollution. It defines pollution as unusually high concentrations of harmful substances that make the environment impure. It identifies major air pollutants such as sulfur dioxide, nitrogen oxides, and carbon monoxide that are emitted from vehicles, factories, and volcanoes. Air pollution causes health problems, environmental damage, and acid rain when sulfur dioxide and nitrogen oxides dissolve in water. Acid rain damages trees, statues, and the Taj Mahal. The document also defines water pollution as contamination from wastewater, sewage, and industrial waste that degrades aquatic ecosystems and harms human health. The key causes of both air and water pollution are from vehicles, factories, and other human activities.