Smita Chowdhury is pursuing her Ph.D. degree in Chemistry from Department of Chemistry, Gauhati University, Assam. She is currently working as a subject teacher of Chemistry in Jorhat Govt Girls’ H.S. & M.P. School, Jorhat, Assam. Her research work is mainly based on application of catalysis for treating wastewater containing toxic pollutants. She has successfully used methods like advanced oxidation processes (AOPs) for treatment of various dyestuffs with the help of different types of clays. Her research work is already published in reputed international journals. Her experience in the topic of environmental chemistry has resulted in writing a chapter in this book.