The Commission for Air Quality Management (CAQM) on Saturday, January 17, 2026, reimposed Stage IV of the Graded Response Action Plan (GRAP) across Delhi-NCR. This decision came as the region's air quality sharply deteriorated, officially slipping into the 'severe' category. The Air Quality Index (AQI) in Delhi, which was 400 at 4 PM, surged to 428 by 8 PM, prompting the activation of the highest level of pollution control measures. While GRAP Stage IV is typically triggered when the AQI exceeds 450 (classified as 'severe+'), the CAQM acted proactively to prevent further escalation of the pollution crisis. Under GRAP-IV, stringent restrictions have been put into immediate effect. These include a complete ban on non-essential construction and demolition activities, the shutdown of polluting industries, and significant limitations on the movement of diesel vehicles, particularly those not compliant with BS-VI norms or not registered in Delhi. The measures also prohibit open burning and the use of diesel generators, except for essential services. Educational institutions and offices may also be advised to shift to online or remote working modes to protect vulnerable populations. This reimposition follows the enforcement of GRAP-III just a day prior, highlighting the rapid worsening of air quality attributed to factors like stagnant winds, winter conditions, and unchecked emissions. The recurring air pollution in Delhi-NCR poses serious health risks, making the implementation of these emergency measures critical for public well-being.