Air pollution is caused by excessive amounts of unwanted gases in the atmosphere from various sources such as vehicles, factories, power plants, and natural sources. The main types of air pollution include smog, acid rain, and greenhouse gases that cause global warming. The effects of air pollution are serious and include health impacts from smog, environmental damage from acid rain, and long-term consequences of global warming such as rising sea levels. One example is the Taj Mahal, where air pollution is discoloring and corroding the white marble monument. Reducing activities that produce air pollution can help prevent further damage.