Airshed-Based Approach To Combat Air Pollution
Source: Indian Express
GS III: Environment, Pollution and Climate Change
Overview
- Winter air pollution is driven by vehicular emissions, road dust, industrial activities, waste burning and stubble burning, along with unfavorable weather conditions.
- El Niño may indirectly influence winter pollution by affecting rainfall and atmospheric conditions that determine pollutant dispersion.
- Stubble burning in Punjab and Haryana highlights the regional nature of air pollution and the limitations of city-centric control measures.
- An airshed-based approach, supported by scientific forecasting, satellite monitoring, inter-state coordination and emission control, is essential for long-term air-quality improvement.
Why in the News?
Delhi is preparing for its winter pollution season through measures such as road sweeping, work-from-home provisions and the Graded Response Action Plan (GRAP).
News in Brief
- Winter air pollution results from stubble burning, waste burning, vehicular emissions, road dust and unfavorable weather conditions.
- During the 2023–24 El Niño-influenced monsoon, India recorded a 13% rainfall deficit, while Delhi received 17% above-normal rainfall.
- El Niño may indirectly worsen winter pollution by influencing western disturbances, rainfall and atmospheric conditions that trap pollutants.
- Stubble burning in Punjab and Haryana adds to regional pollution, highlighting the need for an airshed-based approach supported by scientific forecasting, satellite monitoring and inter-state coordination.
Delhi’s Air Pollution
- Delhi’s air pollution is the result of both local emissions and pollution transported from surrounding regions.
- Major sources include;
- Vehicular emissions: A significant source of PM2.5, along with other harmful pollutants.
- Road dust: Construction activities and dust from roads contribute substantially to particulate pollution.
- Stubble burning: Agricultural residue burning in Punjab and Haryana adds to regional pollution during the post-monsoon season.
- Waste and biomass burning: Open burning releases particulate matter and other harmful pollutants.
- Industrial emissions: Industries and other combustion-based activities contribute to deteriorating air quality.
- Although transport was identified as a major contributor to Delhi’s PM2.5 pollution in earlier studies, pollution-control priorities have often focused on dust because of its importance in the National Clean Air Programme (NCAP).
- Therefore, policies must be guided by updated scientific evidence rather than a narrow focus on individual pollution sources.
Role of El Nino and Weather Conditions
- El Nino is a climate phenomenon involving the warming of surface waters in the central and eastern equatorial Pacific Ocean.
- Although it is not a direct source of air pollution, it can influence atmospheric and weather conditions that worsen pollution.
- It should not be treated as a pollution source itself.
How can El Nino affect Delhi’s winter pollution?
- Weaker western disturbances
- These weather systems bring rainfall to northern India and help wash away pollutants.
- Their weakening can reduce this natural cleansing.
- Reduced rainfall
- Less rainfall allows pollutants to remain suspended in the atmosphere for longer.
- Poor atmospheric dispersion
- Stagnant weather and reduced wind speeds prevent pollutants from dispersing.
- Temperature inversion
- A combination of milder daytime temperatures and stagnant conditions may lower the atmospheric mixing layer, trapping pollutants close to the ground.
As a result, pollution from vehicles, stubble burning and other sources can accumulate rapidly, triggering severe pollution episode.
Stubble Burning: A Regional Challenge
- Punjab and Haryana have experienced severe rainfall deficits, with deficits reaching approximately 23-40% in some areas.
- Early monsoon rains enabled some farmers to sow paddy earlier, potentially allowing harvesting to begin as early as the first week of October.
- However, the effect of rainfall deficits on the rice crop and subsequent stubble-burning patterns remain uncertain.
- Key Concerns
- Stubble burning contributes to regional particulate pollution.
- Satellite-based fire detection helps identify burning incidents.
- Farmers may resort to burning when suitable alternatives are unavailable or costly.
- Delayed action during the early stages of the burning season can allow pollution to intensify.
- Solution– Authorities must provide affordable crop-residue management alternatives and engage farmers rather than relying exclusively on enforcement.
Why is an Air-based Approach Necessary?
- An airshed is a geographical region within which air pollutants move and interact, regardless of administrative boundaries.
- Delhi’s air quality is influenced by emissions and atmospheric conditions across the wider Indo-Gangetic Plain.
Limitations of the city-centric approach
- Pollution crosses state and city boundaries.
- Local restrictions cannot control emissions originating in neighboring regions.
- Weather conditions can transport and concentrate pollutants over large areas.
- Short-term emergency measures do not address the structural causes of pollution.
Airshed-based approach
- Coordinate pollution-control measures across Delhi, Punjab, Haryana and other affected regions.
- Identify the contribution of different pollution sources through scientific studies.
- Use satellite monitoring and forecasting to detect pollution hotspots.
- Integrate agricultural, industrial, transport and urban pollution-control policies.
- Adopt measures across short-, medium- and long-term timeframes.
Government Initiatives
- National Clean Air Programme (NCAP): Aims to improve air quality through city-level action plans and pollution mitigation.
- Graded Response Action Plan (GRAP): Provides emergency measures to address deteriorating air quality in Delhi-NCR.
- System of Air Quality and Weather Forecasting and Research (SAFAR): Supports air-quality forecasting and the assessment of pollution sources.
- National Air Quality Resource Framework of India (NARFI): Developed by the National Institute of Advanced Studies (NIAS) to strengthen scientific understanding and air-quality management.
Measures Needed
- Adopt airshed-based governance: Move beyond isolated city-level interventions towards coordinated regional planning.
- Strengthen scientific forecasting: Combine meteorological data, emission inventories and satellite-based monitoring.
- Reduce emissions at source: Address transport, road dust, industrial emissions, waste burning and agricultural residue burning.
- Support farmers: Make crop-residue management technologies accessible and economically viable.
- Improve accountability: Evaluate pollution-control measures based on actual improvements in air quality.
- Develop a satellite airshed: Explore satellite-based systems as an operational alternative for regional air-quality monitoring and management.
The satellite-based airshed management could offer an alternative to the full implementation of a ground-based airshed framework, but its practical feasibility requires careful assessment.
Conclusion
Delhi’s winter pollution is not merely a local environmental pollution; it reflects the interaction of regional emissions, climate variability and unfavorable weather conditions.
India must move from a city-centric approach to an airshed-based, science-driven strategy that combines regional cooperation, reliable forecasting, emission reduction and long-term planning. This is essential for achieving cleaner air and protecting public health.
UPSC Prelims and Mains Practice Question
With reference to air pollution and its management in India, consider the following statements:
1. An airshed is a geographical region within which air pollutants move across administrative boundaries.
2. El Niño directly emits particulate matter, thereby increasing winter air pollution in northern India.
3. The National Clean Air Programme (NCAP) aims to improve air quality through pollution-control measures.
Which of the statements given above is/are correct?
(a) 1 and 2 only
(b) 1 and 3 only
(c) 2 and 3 only
(d) 1, 2 and 3
Answer: (b) 1 and 3 only
Mains Practice Question
Q) Air Pollution requires an airshed-based approach rather than city-centric interventions. Discuss the challenges in managing regional air pollution in India and suggest measures to address them. (150 words)
Daily Current Affairs: Click Here