Indoor air pollution and fine mode particulate matter with an aerodynamic diameter smaller than 2.5 micrometers (PM2.5) is a major contributor to global morbidity and mortality, particularly due to cardiovascular disease. This project aims to demonstrate the efficacy, feasibility and effectiveness of portable air filters in improving indoor PM2.5 levels and improving functional capacity of heart failure patients with reduced ejection fraction in India. The findings from the project will add to existing knowledge of innovative and scalable strategies to improve environmental and cardiovascular health worldwide. The overall objective of this study is to demonstrate the efficacy, feasibility, and effectiveness of portable air filters in improving indoor PM2.5 levels and improving functional capacity of heart failure patients with reduced ejection fraction in India.