Delhi-NCR’s Elevated PM2.5 Levels Not Primarily Linked to Punjab-Haryana Agricultural Fires

In a groundbreaking study led by the Aakash Project, researchers have unveiled critical insights into the air pollution crisis affecting the northern Indian states of Punjab and Haryana, particularly during the peak period of crop residue burning (CRB). International collaboration, involving the Research Institute for Humanity and Nature (RIHN) and the Japanese Agency for Marine-Earth Science and Technology (JAMSTEC), has unveiled a clear link between CRB and the alarming levels of particulate matter (PM2.5) detected in the atmosphere. The summer harvest, primarily of rice, often leads to widespread burning of leftover agricultural residue, a practice entrenched in tradition and agricultural practice, as farmers strive to clear fields quickly for the next sowing.

The study utilized a comprehensive network of thirty low-cost sensors deployed throughout Punjab and Haryana to monitor air quality in real-time. These sensors, known as CUPI-Gs, have been instrumental in continuously recording air pollutants across two consecutive years, 2022 and 2023. The researchers developed innovative analytical methods to track the formation and dispersion of air pollutants, thus allowing a deeper understanding of the causative factors behind pollution levels, particularly during the critical October-November months, known for rapid air quality degradation.

Despite prior assumptions about the significant contribution of agricultural practices to air quality deterioration in major urban centers, the findings reveal a more nuanced reality. The air pollution generated by CRB does indeed impact rural and semi-urban areas, but its contribution to pollution levels in the National Capital Region (NCR) of Delhi is comparatively reduced. With meticulous data collection spanning two years, the research assists in validating or refuting previously held beliefs regarding the relationship between farming activity and air quality.

The alarming consequences of hazy skies and poor air quality during the harvest months have implications not only for human health—evident from rising cases of respiratory ailments—but also for the broader economy. Policymakers have long grappled with proposals aimed at changing the agricultural practices of farmers, promoting strategies that mitigate the impact of open burning on air quality. However, one of the major challenges in this discourse arises from the lack of ongoing systematic measurements, as traditional methods often rely on sporadic data rather than real-time observations.

The research emphasizes that even as satellite fire detection counts have drastically decreased over recent years, air quality measurements in Delhi have remained alarmingly high. The data collected during the peak CRB days revealed daily mean PM2.5 levels surged beyond 300 μg per cubic meter, underscoring the extent of the challenge. The analysis also identified critical variations in meteorological conditions between 2022 and 2023, which greatly influenced the transport of pollutants from Punjab and Haryana to the NCR.

In November 2022, favorable northwesterly winds facilitated the migration of air masses laden with pollutants from the burning fields into Delhi. Conversely, in November 2023, a stark contrast was observed, where a shift in wind patterns resulted in stagnant air, causing trapped local pollutants to accumulate and significantly degrade air quality. These findings carry critical implications for policymakers, as they suggest that local emissions may play a larger role in aggravating pollution levels compared to the transboundary impact of agricultural burning.

Prof. Prabir Patra, leader of the Aakash Project, outlined the significance of having a cohesive network of 30 measuring sites as a game-changer in accurately dissecting PM2.5 contributions. This unprecedented resolution allows researchers to draw distinct connections between atmospheric data and agricultural practices, which could inform targeted intervention strategies. Multiple years of data collected empower the research team to accurately characterize those contributions associated with periodic agricultural burning.

This study’s findings radically shift the narrative surrounding air pollution in Delhi, revealing the extent to which local practices—combined with various meteorological factors—play roles in shaping air quality dynamics. The research points to systemic issues that require crucial attention from both stakeholders and the scientific community. Academics and citizens alike will benefit from the timely release of air quality data, allowing for a more informed discourse on public health implications and environmental responsibility.

The analyses were supported by comprehensive methodologies, ranging from the interpretation of air mass trajectories and fire counts to advanced chemical-transport simulations, weaving a complex narrative of cause-and-effect relationships in air quality dynamics. The partnership between community stakeholders and researchers has facilitated open data sharing, promoting transparency and public engagement in solving one of the most pressing issues in urban environmental health today.

What emerges from this research is not just data, but a call to collective action. The study highlights the importance of sustaining active dialogue regarding the roles of agriculture and air quality. Institutional collaboration from research bodies and government agencies is paramount for developing actionable solutions that consider both agricultural sustainability and public health. As climate change dynamics continue to influence weather patterns, this legislative discourse becomes not just urgent but indispensable.

The implications are clear: continuous monitoring of air pollutants in not just the originating regions of Punjab but also in impacted areas like Delhi is crucial for policy formulation and effective implementation of air quality management strategies. Regional cooperation among states, driven by empirical evidence, will be vital in addressing the air quality crisis and safeguarding public health.

This research underscores the robustness of data-driven approaches in tackling environmental issues. The Aakash Project serves as a model for how targeted and sustained research can facilitate innovative public health policies, ultimately leading to a healthier environment. As environmental scientists and policymakers unite with communities, an integrated approach to solving the pervasive issue of air pollution may well be achievable, one data point at a time.

As this research gains traction, ongoing dialogues with farmers and stakeholders must emphasize sustainable agricultural practices, leading to a reduction in stubble burning while maintaining soil fertility and yield. Empowering farmers with knowledge of sustainable practices is essential for mitigating the impact of air pollution, challenging the status quo of agricultural traditions that inadvertently harm air quality. The Aakash Project extends its vision beyond mere academic inquiry, striving for a future where sustainable practices are intrinsic to agricultural policies, benefiting local communities and the broader environment alike.

In the pursuit of understanding and addressing air pollution caused by crop residue burning in North India, the collective responsibility encompasses not only researchers and policymakers but also the farmers and citizens who will be instrumental in creating a cleaner and healthier environment for generations to come.

Subject of Research: The impact of crop residue burning on air quality in Punjab and Haryana and its implications for Delhi-NCR.

Article Title: Weak coupling of observed surface PM2.5 in Delhi-NCR with rice crop residue burning in Punjab and Haryana.

News Publication Date: 15-Jan-2025.

Web References: Aakash Project, RIHN Data Set.

References: Mangaraj et al. (2025).

Image Credits: Aakash Project, RIHN.

Keywords: Air pollution, CRB, PM2.5, Aakash Project, Punjab, Haryana, Delhi-NCR, Environmental science, Sustainable agriculture.

Tags: Aakash Project research findingsagricultural fires impact on air qualityagricultural practices and air pollutioncrop residue burning effectsDelhi air pollution crisisinnovative pollution tracking methodsinternational collaboration on pollution researchlow-cost air quality sensorsPM2.5 levels in Delhi-NCRPunjab-Haryana air quality studyreal-time air pollution monitoringseasonal air quality degradation