Your Cilia Are Being Paralysed
The lungs' first line of defence is a carpet of microscopic hair-like structures called cilia, which beat rhythmically to sweep dust, bacteria, and debris up and out of the airways. PM2.5, particulate matter smaller than 2.5 micrometres, the dominant pollutant on high-AQI days across Delhi, Mumbai, and Kanpur, doesn't get swept. It's too small. Worse, sustained exposure to PM2.5 and nitrogen dioxide slows and eventually paralyses ciliary movement. A 2019 study published in the European Respiratory Journal found that urban residents exposed to chronic traffic pollution showed measurably reduced mucociliary clearance rates compared to rural controls. Once the cilia stop working efficiently, everything else the lungs try to do becomes harder.
