Catalytic reduction is a chemical process that uses a catalyst to convert harmful substances into less harmful ones. This method is commonly used in automotive exhaust systems to reduce emissions of nitrogen oxides (NOx), which are pollutants that contribute to smog and acid rain. The catalyst, often made from precious metals like platinum or palladium, facilitates the reaction without being consumed in the process. In this process, the NOx gases are transformed into nitrogen and oxygen, which are harmless and naturally present in the atmosphere. Catalytic reduction is an essential technology for meeting environmental regulations and improving air quality, making it a key component in modern vehicles and industrial applications.