Tackling air pollution requires science-based plan, not just GRAP

Why in the News

Delhi’s Winter Action Plan began this month with vehicle, construction and fuel curbs such as “No PUCC, No Fuel” (no fuel without a Pollution Under Control Certificate), yet the air turned “Very Poor” on its first day. The plan rests on weak fire data, a Delhi-only frame and emergency curbs.

What is GRAP, and why is it not enough?

1. What it is: The Graded Response Action Plan (GRAP) is a set of emergency curbs in the National Capital Region (NCR). The curbs tighten in stages as air quality worsens.
2. Emergency, not cure: GRAP works like intensive care for a chronic patient: quick relief at peaks, but no cure. It also repeatedly inconveniences the public.
3. What is missing: Lasting gains need long-term emission cuts at the identified sources.
4. The takeaway: Without a plan aimed at causes, Delhi will keep managing pollution episodes every winter instead of preventing them.

Why did this season’s pollution peak arrive late?

1. Delayed onset: Delhi’s peak pollution season began almost two weeks late. The delay is linked to a Super El Niño, an unusually strong Pacific warming, and rain from Cyclone Arnab.
2. Competing weather effects: Slow winds trap pollutants, but a delayed, milder winter kept levels lower at first. Rainfall deficits also delayed paddy harvesting in Punjab and Haryana.

Why are stubble fire counts unreliable?

1. Fixed overpass times: NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) sensors on the Terra and Aqua satellites pass over Punjab and Haryana outside burning hours. The gap has widened since 2023.
2. Shift to afternoon burning: Most of Punjab’s stubble fires now start late in the afternoon, after the satellites pass, so official counts miss them.
3. Geostationary view: South Korea’s Korea Multi-Purpose Satellite-2A (KOMPSAT-2A) stays fixed over one region, so its Advanced Meteorological Imager maps it continuously. It detects far more Punjab fires than official estimates.
4. Modelled share: National Institute of Advanced Studies (NIAS) modelling with realistic stubble emissions matches the first day’s sudden PM2.5 (fine particle) rise. It attributes about 20% of Delhi’s PM2.5 to stubble burning.

What would a science-based plan look like?

1. Airshed approach: An airshed is the whole region whose emissions and weather shape a city’s air, across administrative borders. A Delhi-only approach misses a large share of the city’s sources.
2. AIRSHEDEM: A National Institute of Advanced Studies (NIAS) study for the Office of the Principal Scientific Adviser proposes an indigenous framework, “AIRSHEDEM”. Master planning on an airshed basis lets pollution control reach nearly all the sources.
3. Workable boundary: The proposed airshed is neither the entire NCR nor only the National Capital Territory (NCT) of Delhi, so it stays scientifically sound and administratively feasible.

Challenges

1. Harder weeks ahead: Stubble burning, unstable early-winter weather and high-emission episodes are likely to converge over the next 30 to 40 days.
2. Fog and fewer disturbances: Deeper winter brings fog from the Indo-Gangetic Plain, possibly worsened by fewer western disturbances, the weather systems that bring rain and clean the air.
3. Year-round sources: Congested junctions, poorly maintained roads, weak traffic management and open waste burning pollute all year.

Way Forward

1. Continuous fire data: Subscribe to geostationary satellite fire data and feed it into official forecasts.
2. Airshed master plan: Adopt airshed-based planning that covers sources outside Delhi NCT.
3. Year-round action: Fund sustained work on junction congestion, road upkeep and open waste burning, beyond winter curbs.
4. Model-led warnings: Use realistic stubble emissions in forecasts to act before GRAP stages are triggered.

Conclusion

Delhi’s winter response is still built around emergency curbs, which relieve the worst days but leave most sources untouched. Whether authorities adopt airshed-wide planning and better satellite inputs will decide if the city moves from managing episodes to reducing emissions.

Key numbers

1. Afternoon stubble fires, Punjab: Over 90% of events occurred after 3 PM in 2024 and 2025, against under 3% in 2021.
2. Source coverage: A Delhi-only approach covers 50% to 70% of emission sources affecting the city; airshed planning comes close to 100% (NIAS).

Government Initiatives on Air Pollution

1. National Clean Air Programme (NCAP): Launched by the Environment Ministry in 2019, it funds action plans in cities that fail national air quality standards.
2. Commission for Air Quality Management (CAQM): A statutory body under the Commission for Air Quality Management in National Capital Region and Adjoining Areas Act, 2021. It enforces GRAP across States.

Matching Previous Year Question

“[2021, GS3, 10 marks] Describe the key points of the revised Global Air Quality Guidelines (AQGs) recently released by the World Health Organisation (WHO). How are these different from its last update in 2005? What changes in India’s National Clean Air Programme are required to achieve these revised standards?”