Delhi's air quality has significantly deteriorated, with the overall Air Quality Index (AQI) reaching 390-391, placing it in the 'very poor' category and nearing 'severe' levels. Numerous monitoring stations reported AQI above 400, indicating severe pollution in specific areas. This worsening air quality is attributed to a combination of cold temperatures, calm winds, and dense fog trapping pollutants. Authorities are monitoring the situation, enforcing measures like the 'No PUC, No Fuel' rule, and have invoked Stage III/IV of the Graded Response Action Plan (GRAP), including restrictions on construction and industrial activities. The India Meteorological Department has issued an orange alert for dense fog.