Delhi’s air quality plunged further on Monday prompting the Commission for Air Quality Management (CAQM) to enforce Stage IV of the Graded Response Action Plan (GRAP) from Monday night. This comes after the AQI rose to 399 at 9 pm and breached the 400 mark at 10 pm. The GRAP 4 measures were introduced within hours of implementing Stage III restrictions earlier in the day, when the AQI hovered over 300, indicating severe pollution levels. According to CAQM, the deteriorating air quality is attributed to highly unfavourable meteorological conditions, including stagnant winds and an extremely low mixing height, which have trapped pollutants near the ground.
Ban on all construction activities
According to an official order, the curbs under Stage 4 of the Graded Response Action Plan for winters include a ban on all construction and demolition activities, including public projects such as highways and flyovers, and on the entry of trucks carrying non-essential goods into Delhi. The national capital’s 24-hour average air quality index, which was 379 at 4 pm, breached the 400 mark around 10 pm amid extremely calm winds and “buildup of an inversion layer adversely affecting the vertical mixing height”. Vertical mixing height is the height above the surface throughout which a pollutant can be dispersed.
What is GRAP-4?
The Graded Response Action Plan is a set of anti-pollution measures implemented in the Delhi-NCR region to combat air pollution based on its severity. Stage 4, the most stringent level, is triggered when the Air Quality Index crosses 400, indicating a “Severe+” (emergency) air quality situation. The primary goal of GRAP-4 is to reduce immediate emissions and alleviate the impact of air pollution on public health, especially for vulnerable populations like children, the elderly, and individuals with respiratory ailments. By implementing GRAP-4, authorities aim to restore air quality to safer levels while encouraging long-term strategies to address the recurring pollution crisis in Delhi-NCR.
