CS gas, also known as tear gas, is a chemical compound used primarily for crowd control and self-defense. It causes temporary irritation to the eyes, skin, and respiratory system, leading to symptoms like tearing, coughing, and difficulty breathing. The effects usually subside within 15 to 30 minutes after exposure. Originally developed in the 1920s, CS gas is often deployed by law enforcement during riots or protests to disperse crowds. While it is considered a non-lethal option, its use has raised concerns about safety and human rights, especially in enclosed spaces or against vulnerable populations.