You fill your car with gasoline, the engine burns the gas, turns it into exhaust, and blows it out the tailpipe.

No engine is 100% efficient, which means leftovers, or pollutants are created as it burns fuel. Those pollutants have to be processed out of the engine, in the form of exhaust, otherwise the engine can’t function. Your car’s exhaust system has a lot of work to do, so it’s important to have it serviced.

Infographic on parts and how a car's exhaust system works