It is known that cardiovascular diseases are the major contributor to deaths every year worldwide. Most of these are due to atherosclerosis, a disease in which plaque builds up inside the arteries in the heart, brain, arms, legs, pelvis or kidneys, thus, leading to the development of Coronary heart disease, Carotid heart disease, Peripheral heart disease, chronic kidney disease. In this talk, I present our work on the blood flow dynamics in a diseased human coronary artery caused due to atherosclerosis. This study is essential, particularly in the current situation where COVID-19 has affected the majority of the population across the globe, and studies have revealed that COVID-19 patients are more at risk for the occlusions in arteries and veins [1]. In our work, we developed numerical models using idealized geometry for the carotid artery with Newtonian and non-Newtonian models for blood.