North Indian winters were once crisp, clear, and pleasant. Today, stepping outside without a mask can feel unsafe. After spending more than a decade studying air pollution, from researching immune damage in college to building high efficiency purifiers for Indian homes, I have learned that choosing the right air purifier is not as simple as online reviews make it seem.

This guide condenses years of research, engineering, and personal experience into practical advice. You will learn what air pollution is, how different pollutants affect your health, how to calculate the right CADR for your room, and why many popular features including air purifying plants do not actually help. Whether you are buying a purifier or building one yourself, this blog will help you avoid common mistakes, understand what truly matters, and make your home safer this pollution season.