SCR technology is a method used to reduce harmful nitrogen oxides (NOx) in exhaust gases by converting them into harmless nitrogen and water. It is a widely used and effective technology due to its high efficiency and ease of operation. Recent global regulations have increased the focus on SCR technology for NOx reduction. Catalysts like vanadium, tungsten oxides, manganese, cerium oxides, and zeolites are commonly used in NH3-SCR. However, issues like catalyst deactivation by sulfur compounds and high temperatures require careful design and regeneration techniques for optimal performance. Developing advanced catalyst technologies is crucial to meet stricter emission regulations for reducing NOx emissions.