A recent scientific study has provided concrete evidence that the Graded Response Action Plan (GRAP), the emergency protocol activated during Delhi-NCR's toxic air episodes, is a powerful tool in safeguarding public health. Research conducted by the Indian Institute of Tropical Meteorology, Pune (IITM-Pune) and the Commission for Air Quality Management (CAQM) concludes that GRAP significantly improves air quality, preventing a substantial number of severe pollution hours and premature deaths.
GRAP's Measurable Impact on Pollution and Health
The study, titled "Possible effectiveness of the Graded Response Action Plan restrictions in New Delhi, India," offers a stark comparison. It found that without the interventions under GRAP, Delhi could have endured 60% more hours of 'severe' Air Quality Index (AQI) levels. Furthermore, hours of 'severe-plus' category pollution could have been 60% to 200% higher. The plan's staged restrictions successfully reduced concentrations of deadly fine particulate matter (PM2.5) by 2 to 42 micrograms per cubic metre (µg/m³), depending on the severity stage enacted.
This direct reduction in pollution translates into saved lives. The researchers estimate that GRAP's actions potentially prevented between 177 and 297 short-term deaths and saved a collective 8,615 to 14,456 years of life that would have been lost to the hazardous air.
How GRAP Stages Curb Pollution Step-by-Step
GRAP is a graded system triggered as the AQI deteriorates. Each stage brings in stricter measures:
- Stage I: Focuses on rigorous enforcement of existing dust and waste management rules.
- Stage II: Implements measures like staggered office timings, a ban on polluting interstate buses, and higher parking fees to deter private vehicles.
- Stage III: Escalates to a ban on most construction and demolition, restrictions on older petrol and diesel vehicles, closure of stone crushers, and a shift to hybrid learning for primary school students.
- Stage IV: Enforces the strictest measures, including a ban on non-essential truck entry, expanded hybrid schooling, and further curbs on non-BS-VI private vehicles.
The data from the past two years shows variation in both pollution levels and enforcement duration. For instance, during GRAP Stage IV in the 2022-23 period, the PM2.5 mean was 47.6 µg/m³, which decreased to 37.4 µg/m³ in 2023-24. This stage was active for 31 days in 2022-23 but only 3 days in the following year.
Experts Affirm GRAP's Role as a Critical Health Shield
While acknowledging the inconvenience caused by the restrictions, environmental and policy experts unanimously stress the plan's indispensable public health benefits.
Anumita Roychowdhury of the Centre for Science and Environment (CSE) stated that GRAP helps prevent pollution peaks and flattens dangerous AQI spikes, serving as an early public health warning system.
Dipankar Saha, former head of the Central Pollution Control Board (CPCB), emphasized that the primary goal is protecting health, and finding alternative solutions can help minimize public disruption.
Sachin Ghude from IITM-Pune, a key author of the study, quantified the impact, noting that GRAP reduced the AQI by up to 49 units. He reinforced that Delhi would have recorded far more severe air quality hours without this emergency plan.
The study solidifies GRAP's position as an essential, life-preserving intervention for Delhi-NCR. It acts as a necessary "mini-lockdown" against air pollution, underlining the critical need for continued enforcement, public cooperation, and long-term solutions to achieve clean air.
