Residents of Delhi and the National Capital Region (NCR) woke up to a grey, foggy morning on December 19, 2025, as a thick blanket of fog engulfed the city. The India Meteorological Department (IMD) has issued a Yellow Alert, warning of dense to very dense fog that has significantly reduced visibility to less than 100 meters in several areas, including Palam and Safdarjung. This weather pattern is compounded by a dangerous spike in pollution levels, with the Air Quality Index (AQI) teetering on the brink of the 'severe' category. The toxic combination of smog and fog, often referred to as "smog," is causing major disruptions to aviation and vehicular movement while posing serious health risks to vulnerable groups.