There are a number of reasons why catalytic converters are stolen by thieves. One reason is that catalytic converters are made of platinum and other precious metals, which make them a valuable commodity on the black market. Another reason is that catalytic converters can be easily removed from cars without causing any damage, so they are an easy target for thieves. Finally, there is a large demand for catalytic converters in countries like China and India, where they are used in manufacturing industries.