Context:
- The air pollution in Delhi spikes to 10 times over WHO limit.
- According to CPCB data, the level of hazardous PM 2.5 – tiny particles that are 2.5 microns or less in diameter – was recorded at 160 micrograms per cubic meter at 9 a.m. on 27th October against the permissible limit of 15 micrograms per cubic meter for a 24-hour period.
- This week, the city have consistently recorded PM 2.5 levels exceeding 300, or ‘very poor’ air quality.
Major factors behind pollution crisis in Delhi:
Stubble burning: Farmers in Punjab and Haryana burn crop residues to clear their field for the next season. This produces a lot of smoke and PM responsible for dip in air quality over Delhi.
In 2023, a study conducted by a consortium of IIT Kanpur, IIT Delhi, TERI and Airshed, Kanpur, found that from mid-October to the end of November 2022, the role of stubble burning to air quality was on average 22% and peaked to as much as 35%.
Composition of Stubble burning: Stubble burning emits toxic pollutants in the atmosphere containing harmful gasses like Carbon Monoxide (CO), methane (CH4), carcinogenic polycyclic aromatic hydrocarbons, volatile organic compounds (VOC).
Note: To some extent Punjab’s 2009 law (the Punjab Preservation of Subsoil Water Act) also responsible behind stubble burning. (this law barred farmers from paddy sowing in nurseries before May 15 and transplanting before June 15.
Wind direction: Wind direction plays a significant role in Delhi’s air pollution, especially during the winter months. The predominant direction of winds in Delhi is north westerly post-monsoon.
- According to a study conducted by National Physical Laboratory, 72% of Delhi’s wind in winters comes from the northwest.
Temperature Inversion:
- Temperature inversion is a phenomenon that occurs when the air temperature increases with altitude, instead of decreasing as usual. This creates a layer of warm air above a layer of cold air, trapping the pollutants near the ground.
- Temperature inversion affects Delhi’s pollution in winter, when the weather is cold and calm. The pollutants from stubble burning, vehicle emissions, industrial emissions, and other sources accumulate in the lower atmosphere and form a thick layer of smog.
Still Air:
In winters, there is less rainfall and wind speed, which means that the pollutants do not get washed away or diluted by fresh air. The pollutants remain suspended in the air for longer periods of time.
Other Miscellaneous Factors:
- Dust storms
- Firecrackers
- Biomass Burning
Initiatives taken by government to tackle air pollution in Delhi:
In October 2024, Delhi government launched a comprehensive 21-point winter Action Plan. It comprises:
- Deployment of Drones to monitor 13 pollution hot spots in Delhi
- Public participation like e-vehicle parade, an anti-pollution march, and the “Red Light On, Gaadi Off” Initiative etc.
- Anti dust campaign: Use of water sprinkler and anti-smog guns.
- Artificial Rain
Green War Room: A nine-member team that monitors the actions taken by 20 government agencies against pollution on a real-time and daily basis.
Activation of GRAP: The Commission for Air Quality Management (CAQM) in NCR and adjoining areas oversees the implementation of GRAP.
- The CAQM has constituted a sub-committee for the operationalization of the GRAP.
Different Stages Of GRAP:
GRAP consists of four stages, each with targeted actions to be taken by the necessary authorities and agencies. These are the following:
Stage I: Poor” air quality (Delhi AQI: 201-300)
Stage II: Very Poor” air quality (Delhi AQI: 301-400)
Stage III: Severe” air quality (Delhi AQI: 401-450)
Stage IV: Severe+” air quality (Delhi AQI > 450)
conclusion
Delhi’s air pollution crisis is a multifaceted issue driven by various factors such as stubble burning, wind direction, temperature inversion, and still air during winter months. The alarming levels of PM 2.5, often exceeding safe limits by a significant margin, highlight the urgent need for effective measures.
The Delhi government’s proactive steps, including the 21-point winter Action Plan, deployment of drones, public participation initiatives, and the activation of the Graded Response Action Plan (GRAP), are commendable efforts to combat this pressing issue. However, sustained and collaborative efforts from all stakeholders, including neighboring states, are crucial to achieving long-term improvements in air quality.
Addressing Delhi’s air pollution requires a comprehensive approach that combines immediate actions with long-term strategies to reduce emissions and promote cleaner, healthier air for all residents.
