A catalytic converter is an essential part of a vehicles exhaust system that helps lower the number of toxic pollutants emitted into the air by converting hazardous combustion gases into less harmful substances, like water vapor and carbon dioxide. It is designed to convert harmful emissions produced by an internal combustion engine to less-harmful elements, such as H2O (water), CO2 (carbon dioxide), and N2. The catalytic converter contains a thin layer of precious metals on a ceramic structure, which acts as a catalyst to prompt chemical reactions that transform otherwise toxic pollutants into relatively harmless ones. The catalyst essentially ushers a chemical reaction without being consumed itself. The catalytic converter can only function efficiently if the engine is operating properly and the exhaust system is leak-free. Malfunctioning sensors or actuators, damaged engine components, too-rich or too-lean fuel mixtures, and inconsistencies between engine cylinders may lead to converter efficiency issues and possibly damage the catalyst.

In summary, a catalytic converter is a device installed in the exhaust system of a car that converts harmful exhaust gases into cleaner exhaust by using a catalyst to prompt chemical reactions that transform toxic pollutants into less harmful ones.