On Tuesday morning, December 23, 2025, Delhi faced extreme air pollution as thick fog and haze covered the city. The air quality index (AQI) rose sharply, crossing 400 at 27 monitoring stations, placing these areas in the 'severe' category. Five stations recorded AQI above 450, entering the 'severe plus' range. Anand Vihar reported the highest AQI of 470, followed by Nehru Nagar at 463, Okhla and Mundka both at 459, and Sirifort at 450, according to the Central Pollution Control Board's SAMEER app. This level of pollution is known to cause serious health problems. At 9 a.m., Delhi's AQI was 415, worsening from the 'very poor' level seen the previous day. Out of 40 stations, only a few recorded lower AQI levels. The CPCB defines AQI ranges as 'good' (0-50), 'satisfactory' (51-100), 'moderate' (101-200), 'poor' (201-300), 'very poor' (301-400), and 'severe' (401-500). Along with hazardous air quality, dense fog sharply reduced visibility. At 8 a.m., visibility was just 50 metres at Palam and 100 metres at Safdarjung, making travel difficult. Winds were calm or mild, which did not help clear pollution. By 8:30 a.m., visibility improved slightly to 100 metres at Palam and 150 metres at Safdarjung. The India Meteorological Department (IMD) reported Delhi’s minimum temperature at 8.8°C, slightly above the normal by 1.3 degrees. The maximum temperature is expected near 23°C, with dense fog predicted to persist throughout the day.