New Delhi – The contribution of farm fires Delhi to the capital’s PM2.5 pollution has witnessed a dramatic reduction during this year’s burning season, according to official data from the Central Pollution Control Board (CPCB). The farm fires Delhi contribution dropped to just 3.5% from 10.6% recorded last year, representing a significant improvement in air quality metrics. This data was revealed through a Right to Information (RTI) application filed by Noida-based activist Amit Gupta, providing crucial insights into the changing dynamics of Delhi’s air pollution sources.

The declining trend in farm fires Delhi impact marks a notable departure from recent years when stubble burning was considered a major contributor to the capital’s deteriorating air quality during winter months. The figures indicate a consistent reduction compared to recent years, when the average contribution stood at 11% in 2023, 9% in 2022, and 13% in both 2021 and 2020. This substantial decrease suggests that either enforcement measures have become more effective or farmers have adopted alternative methods for crop residue management.

Methodology Behind Farm Fires Delhi Assessment

The CPCB’s assessment of farm fires Delhi contribution relies on estimates from the Indian Institute of Tropical Meteorology’s Decision Support System (DSS). This sophisticated model uses satellite data on active fires across the region, converts this information into emissions data, and then simulates the impact based on prevailing wind patterns and weather conditions. The DSS methodology represents the standard approach for tracking farm fires Delhi and their contribution to air pollution in the national capital region.

The technical framework employed for measuring farm fires Delhi impact involves multiple layers of data processing and atmospheric modeling. Satellite sensors detect thermal anomalies indicative of active fires, which are then processed to estimate emission volumes. These emissions are subsequently tracked using atmospheric dispersion models that account for meteorological variables such as wind speed, wind direction, temperature, and atmospheric stability. This comprehensive approach provides authorities with quantitative estimates of how farm fires Delhi contribute to PM2.5 and PM10 levels in the capital.

Controversy Over Satellite Detection and Timing

Despite the positive trend shown in farm fires Delhi data, some experts have raised concerns about potential underestimation of the actual impact. A recent report by the think tank International Forum for Environment, Sustainability and Technology (iFOREST) revealed that farmers in Punjab and Haryana have increasingly been burning crop residue after 3pm to evade detection by satellites with afternoon pass times. This tactical shift in the timing of farm fires Delhi region could mean many fires go uncounted in daily tallies, potentially skewing the actual contribution figures.

The timing issue surrounding farm fires Delhi detection has emerged as a significant challenge for accurate pollution monitoring. Traditional satellite systems used for detecting farm fires Delhi have specific pass times, typically in the afternoon hours. Farmers who have become aware of these limitations may be deliberately timing their burning activities to avoid detection, thereby circumventing both legal restrictions and monitoring systems. This cat-and-mouse dynamic raises questions about the reliability of satellite-based assessments of farm fires Delhi contribution to air pollution.

CPCB Defense of Data Collection Methods

CPCB officials have defended their methodology for assessing farm fires Delhi contribution, stating that while short-term forecasts use satellite passes until 2.30pm, the system’s final calculations of daily pollution contribution incorporate fire data up to 5pm. According to an official explanation, this extended timeframe ensures more comprehensive coverage. The official stated, “This is why estimates may be inaccurate for fires happening after the satellite pass time of 2.30pm, but the actual contribution has full data.”

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However, this explanation regarding farm fires Delhi monitoring has not satisfied all independent analysts. The question of whether the extended data collection window adequately captures late-evening burning activities remains contentious, particularly given the iFOREST findings about farmers’ adaptive behavior in timing their stubble burning to avoid satellite detection.

Independent Analysts Challenge Farm Fires Delhi Data

Sunil Dahiya, founder of Envirocatalysts, has questioned the accuracy of farm fires Delhi contribution estimates, noting that the DSS relies on fire counts from specific satellites rather than geostationary satellites that can monitor late-evening burns. Dahiya explained that DSS uses an old emission inventory and methodology, which considers fire count incidents through satellites rather than burnt area assessment using geostationary satellites. According to Dahiya, the farm fires Delhi data might be underreporting the contribution of stubble burning to some extent, as highlighted by some of the latest independent assessments done using geostationary satellites.

The critique of farm fires Delhi monitoring methodology suggests that current systems may have structural limitations that prevent accurate assessment of the full impact of agricultural burning on Delhi’s air quality. Geostationary satellites, which maintain a fixed position relative to Earth and can provide continuous monitoring, could offer more comprehensive data compared to polar-orbiting satellites that pass over the same area only at specific times.

Broader Context of Delhi’s Pollution Sources

The RTI response regarding farm fires Delhi also sought details about other sources contributing to Delhi’s PM2.5 and PM10 pollution. In response, CPCB cited a 2018 source apportionment study, highlighting a significant gap in updated research on pollution sources. Activist Amit Gupta noted that the RTI reply highlights two key points: that the contribution of farm fires Delhi is fairly low overall, with other sources likely playing a more significant role, and that stubble burning is not a dominant source of pollution in Delhi but rather one among many smaller sources.

Gupta emphasized the need for updated data, stating, “The fact that we are referring to a 2018 source apportionment study shows we need to update our data.” This observation underscores a critical gap in Delhi’s pollution monitoring infrastructure—while farm fires Delhi receive significant attention and policy focus, the capital may be operating with outdated information about the relative contributions of various pollution sources. A comprehensive, updated source apportionment study would provide policymakers with better information for targeting interventions effectively and allocating resources to address the most significant contributors to Delhi’s air quality crisis.