**Carbon dioxide (CO₂)** is the gas responsible for the **greenhouse effect** in vehicles. This gas is produced when the vehicle's engine burns fuel. Although vehicles are equipped with a **catalytic converter** in the exhaust pipe to reduce pollution, CO₂ remains an inevitable byproduct of combustion.

The catalytic converter helps to decrease other toxic gases, but it does not eliminate CO₂. Therefore, it is important to adopt **efficient driving** practices, such as avoiding sudden accelerations and keeping the engine in good condition, to reduce the amount of CO₂ emitted. Additionally, the use of air conditioning increases fuel consumption, which in turn increases CO₂ production.