Delhi's Air Quality Plunges into 'Very Poor' Category as Winter Smoke and Stubble Burning Worsen Pollution

 Choking Smog in Delhi's Winter Smoke from Stubble Burning in Haryana and Punjab Worsens Air Quality

With the withdrawal of the southwest monsoon and the onset of winter, the air quality in Delhi begins to deteriorate significantly. This phenomenon is marked by consistently high levels of particulate matter (PM 2.5) exceeding 300, categorizing it as 'very poor' air quality. The worsening conditions are anticipated to persist in the coming days due to a combination of factors[1]

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. One of the primary contributors to this decline is the burning of farm stubble, primarily from Punjab and Haryana. Although stubble burning is not the main cause of pollution throughout winter, it remains an episodic problem. According to a central government affidavit submitted to the Supreme Court of India in November 2021, stubble burning contributes to 4% of air pollution in Delhi during winter and 7% during summer. However, other sections of the affidavit indicate that paddy stubble burning can contribute up to 35-40% of the capital's PM 2.5 and PM 10 concentrations, creating a significant outcry among media and experts[2]

Delhi and its neighboring cities, including Noida, Gurugram, Faridabad, and Ghaziabad, experience pollution levels 30-35 times the safe limit recommended by the World Health Organization (WHO) during winter. The air quality deteriorates to 'severe' levels, characterized by a thick layer of smog. Factors contributing to this include plummeting temperatures, smoke, dust, low wind speeds, vehicular emissions, and crop stubble burning[3]

. The onset of winter leads to a reduction in the height at which pollution mixes in the atmosphere, thereby raising its concentration. By late October, as the rains cease, northwesterly winds begin to carry fumes from burning fields into the city. Additionally, the Diwali festival, marked by widespread use of firecrackers, exacerbates the pollution levels[5]

. This combination of factors leads to hazardous air conditions, causing authorities to shut down schools and colleges indefinitely, ban construction work with certain exceptions, and restrict the operation of coal-based power plants[6]

Pollutants Elevated During Stubble Burning Season

During the stubble burning season, specific pollutants see a marked increase, significantly deteriorating Delhi's air quality. PM2.5, a fine particulate matter, is one of the most elevated pollutants during this period. On Sunday, stubble burning contributed to 1.7% of the total PM2.5 pollution, and this figure increased to 2.8% by Monday, October 21. The situation was expected to worsen further, with contributions rising to nearly 7% of PM2.5 concentration in the following days[8]

. Despite common perceptions, studies show that stubble burning accounts for a small but notable fraction of the pollution, with vehicular emissions being a more significant contributor[7]

. Nonetheless, the spike in PM2.5 levels during stubble burning is concerning, as it pushes the Air Quality Index (AQI) into the 'very poor' category, posing severe health risks[7]

. Additionally, the overall annual average PM2.5 concentration in Delhi remains alarmingly high at 101 µg/m³ in 2023, well above the national standard of 40 µg/m³[9]

Health Impacts

The health impacts of the choking smog in Delhi during winter are profound and immediate. The fine particulate matter (PM2.5), which comprises particles that are 2.5 micrometers or less in diameter, is particularly harmful as it can penetrate deep into the lungs and even enter the bloodstream. This can result in a variety of serious health issues, including premature death in individuals with heart or lung diseases, nonfatal heart attacks, irregular heartbeats, aggravated asthma, decreased lung function, and increased respiratory symptoms such as airway irritation, coughing, and difficulty breathing[10]

Studies have shown that both short-term exposure (over hours to days) and long-term exposure (over months to years) to PM2.5 can lead to adverse cardiovascular effects, including harmful impacts on blood vessels and the heart[11]

. Additionally, the pollution can exacerbate conditions such as asthma and chronic obstructive pulmonary disease (COPD), lead to lung cancer, and cause other respiratory issues like wheezing and shortness of breath[13]

Particular groups are more vulnerable to these health impacts. People with pre-existing heart or lung conditions, children, older adults, and those in minority or low socioeconomic status populations are at higher risk due to their increased sensitivity or higher exposure to particle pollution[10]

. Moreover, the entire National Capital Region, including areas like Noida, Gurugram, Faridabad, and Ghaziabad, experiences very high concentrations of particulate matter, exacerbated by slow wind speeds that prolong the presence of these pollutants[14]

To protect oneself during periods of elevated PM2.5 levels, it is advisable to monitor air quality reports and limit outdoor activities when pollution levels are high. Using air purifiers indoors and wearing masks designed to filter out fine particles can also help reduce exposure to harmful particulate matter[10]

Socio-economic Challenges

Despite a series of measures and legal penalties aimed at curbing stubble burning, farmers in Punjab and Haryana continue this practice due to several socio-economic challenges[15]

. Heavy fines have been imposed, with Punjab registering numerous FIRs and significant financial penalties against farmers, yet the scale of the crisis makes enforcement difficult[16]

. Satellite data from the Indian Council of Agricultural Research (ICAR) revealed a drop in stubble burning incidents in Punjab and Haryana, indicating some progress, but the practice remains prevalent[17]

One key reason is the financial burden on farmers. Sustainable alternatives to stubble burning, such as purchasing new machinery for residue management, are often costly and not economically feasible for many farmers[15]

. Even though initiatives have been introduced to support farmers, including subsidies and alternative farming practices, the uptake has been slow due to the high costs involved[15]

Additionally, the urgency to clear fields quickly for the next crop cycle contributes to the persistence of stubble burning[15]

. The short window between harvesting paddy and planting the next crop leaves little time for farmers to manage stubble using methods other than burning[15]

. This seasonal pressure exacerbates the problem, as farmers prioritize immediate crop turnaround over long-term environmental considerations.

Moreover, enforcement of anti-stubble burning laws faces significant logistical challenges. The vast agricultural lands make it difficult to monitor and penalize every instance of stubble burning[16]

. While there has been a reduction in the number of incidents, particularly with Haryana reporting a decline from 14,122 incidents in 2019 to 7,959 in 2023, enforcement remains inconsistent across regions[19]

Mechanisms of Smog Formation

Smog formation in Delhi during the winter months is significantly influenced by the practice of stubble burning in the neighboring states of Haryana and Punjab. Stubble burning involves setting fire to the leftover straw stubble in fields after the harvest of crops such as rice and wheat[23]

. This method is favored by farmers as it is an efficient and cost-effective way to clear the fields for the next planting season[25]

The smoke produced from these fires contains high levels of particulate matter and various noxious gases, which contribute heavily to the dense, choking smog that blankets northern India[23]

. The emissions from stubble burning travel over long distances, often reaching Delhi and worsening the air quality there[24]

This phenomenon is exacerbated during the winter months due to atmospheric conditions that limit the vertical mixing of air. During winter, the height at which pollution mixes in the atmosphere is significantly reduced, leading to higher concentrations of pollutants near the ground[22]

. The problem is further compounded by other pollution sources such as vehicles, coal-fired power plants, and the use of cookstoves, making Delhi's air especially hazardous[26]

In addition to these factors, seasonal changes play a role in worsening the situation. By the end of October, post-monsoon winds from the northwest carry the smoke from burning fields to the capital. Furthermore, the celebration of Diwali with widespread firecracker use adds to the pollution load, making the air quality plummet to dangerous levels[22]

Long-term Public Health Strategies

Reduction of PM2.5 Levels

The World Health Organization (WHO) has underscored the importance of reducing levels of PM2.5 to protect public health, emphasizing that even lower concentrations of air pollution than previously understood can inflict significant damage on human health[27]

. The WHO's Air Quality Guidelines (AQG) have been updated to reflect this, with almost all recommended levels adjusted downwards to mitigate health risks associated with air pollution[27]

. Adhering to these guidelines could potentially save millions of lives globally[27]

To effectively reduce PM2.5 levels in Delhi, particularly in light of the recurring issue of stubble burning in Haryana and Punjab, a multifaceted approach involving both immediate and long-term public health strategies is essential. First and foremost, strict enforcement of the new WHO AQG levels is necessary to ensure that air quality improvements are sustained over time[27]

. This can be achieved through rigorous monitoring and regulation of industrial emissions, vehicular pollution, and construction dust.

Moreover, public awareness campaigns can play a crucial role in educating citizens about the health risks of air pollution and encouraging behavior that reduces personal exposure to pollutants. Implementing green infrastructure, such as increasing urban green spaces and promoting the use of cleaner energy sources, can also help mitigate pollution levels.

In the context of stubble burning, it is imperative to provide farmers with viable alternatives to this practice. This could include subsidies for equipment like Happy Seeders, which allow for sowing without removing crop residue, or incentives for using crop residues in bioenergy production. Collaboration between state and central governments to implement and fund these alternatives will be crucial.

Finally, long-term strategies should involve integrating air quality management into broader public health and urban planning policies, ensuring sustainable development that prioritizes clean air as a fundamental human right[28]

. By addressing the root causes of air pollution and promoting systemic changes, Delhi can move towards healthier air quality and better overall public health outcomes.

Mitigating Health Impacts

The escalation of air pollution in Delhi, especially during the winter months, presents severe public health challenges due to the dangerously high levels of particulate matter (PM2.5). Effective mitigation of these health impacts necessitates a multi-faceted approach that addresses both immediate and long-term concerns.

A critical component of mitigating health impacts involves reducing the sources of pollution. This includes implementing stricter regulations on vehicular emissions and industrial waste, as these are significant contributors to the city’s poor air quality[29]

. Seasonal crop-burning practices in neighboring states like Haryana and Punjab also play a major role in exacerbating pollution levels, making it imperative to find sustainable alternatives to stubble burning[30]

Public health strategies must focus on enhancing the monitoring and forecasting of air quality to provide timely warnings and advisories to the public. This can help individuals take necessary precautions, such as reducing outdoor activities during periods of severe pollution. Additionally, the promotion of indoor air purification systems can help mitigate exposure to harmful pollutants[30]

Investing in healthcare infrastructure to better manage and treat respiratory and cardiovascular conditions caused by long-term exposure to PM2.5 is also crucial. Public awareness campaigns about the health risks associated with air pollution and the importance of wearing protective masks during high-pollution days can further reduce individual risk[31]

Addressing the root causes of pollution, such as the water crisis that drives stubble burning, requires coordinated policy efforts and support for farmers to adopt environmentally friendly practices. This could involve financial incentives for alternative residue management techniques and the promotion of water-efficient farming practices to reduce the need for crop burning[32]

Ultimately, a comprehensive approach that combines regulatory measures, public health initiatives, and sustainable agricultural practices is essential to mitigate the health impacts of Delhi’s air pollution crisis.

Policy Measures and Incentives

The Ministry of Environment, Forests and Climate Change has identified Crop Residue Management as a priority area to prevent air pollution, resulting in extensive deliberations with state governments, pollution control boards, and research institutions[33]

. As a direct response to these discussions, the Commission for Air Quality Management in National Capital Region and Adjoining Areas (CAQM) developed a comprehensive framework to effectively prevent and control stubble burning[33

However, despite these efforts, the Supreme Court has noted a reluctance by the governments of Punjab and Haryana to prosecute farmers for stubble burning, as stipulated under Section 14 of the Commission for Air Quality Management Act, 2021[34]

. The Court has repeatedly expressed its concern over the increasing incidents of stubble burning, especially during critical periods like Diwali, and has demanded an explanation for the non-prosecution of farmers and officials involved in these activities[34]

In terms of positive outcomes, both Punjab and Haryana have recorded notable reductions in fire incidents between 2019 and 2023, attributed to practices such as mulching, in-situ crop residue management, and organic farming[35]

. Furthermore, the Supreme Court has directed these states to implement immediate measures to halt stubble burning and suggested incentivizing farmers to switch from paddy cultivation to alternative crops like millets by offering them the minimum support price (MSP)[36]

The Punjab government has been recognized for its significant efforts, achieving a 71% reduction in stubble burning incidents compared to the previous year[38]

. This progress has been facilitated by enhanced enforcement measures and close monitoring of high-burning districts, although further improvements are still necessary to eradicate the practice entirely[38]

Despite these measures, the issue of stubble burning persists as a significant source of air pollution in northern India, creating a public health crisis that impacts millions of people across the region[39]

. The smoke from burning paddy fields in Punjab and Haryana travels long distances, worsening the air quality in Delhi and other areas[39]

.