In Delhi and the surrounding National Capital Region, mornings are becoming the worst time to breathe — even though road traffic is minimal overnight. Experts point to a wintertime meteorological trap: a phenomenon known as temperature inversion, where cold air settles near the ground while the layer above remains warmer, creating a stagnant “lid” that prevents pollutants from dispersing.

With wind speeds under 8 km/h and moisture levels higher than earlier weeks, particulate matter (PM2.5 and PM10) accumulates rapidly through the early hours, pushing the Air Quality Index into “severe” territory—readings above 400 or 500 are being reported. Contributing factors include not only urban traffic but also night-time emissions from trucks, industrial activity and smoke from stubble burning in surrounding states. 

Public health experts advise avoiding early-morning outdoor activity or morning walks during this period, since the air carries risks of airway inflammation, asthma exacerbation, heart-disease triggers and cognitive impact. Until winds rise and the temperature inversion weakens, mornings in Delhi remain a wartime zone for air quality—and authorities warn that the situation may persist for weeks unless structural changes address emissions and dispersion mechanisms.