4 min readNew DelhiUpdated: Jan 21, 2026 12:16 PM IST
The commission said findings of the new study will be integrated into the Air Quality Early Warning System and DSS to get more accurate and real-time data. (file)
The Commission for Air Quality Management (CAQM) — the pollution watchdog for Delhi-NCR — has said that a source apportionment study has been launched to prepare a new inventory of emissions.
The study will employ high-resolution mapping to track sources — from household heating to crop residue burning — to strengthen the region’s Decision Support System (DSS), a real-time tool to keep a tab on Delhi’s dynamic pollution sources.
The move comes after a CAQM expert panel noted that different studies often yielded different results due to “varying time periods, different locations, different chemical constituents analysed, and different modelling assumptions”. The Supreme Court-mandated panel emphasised that a “unified, data-driven approach” is essential to reduce emission uncertainty and support effective air quality management.
The Indian Express had reported last month that a consortium of institutions led by the Automotive Research Association of India (ARAI), a research body affiliated with the Ministry of Heavy Industries, has been tasked with the study aimed at preparing a new emissions inventory.
The commission said findings of the new study will be integrated into the Air Quality Early Warning System and DSS to get more accurate and real-time data. The consortium — which also includes IIT Delhi, TERI, and IITM Pune — will map emissions on a high-resolution 500 m x 500 m grid.
On Monday, the CAQM released a report titled ‘Identification of the causes for worsening AQI in Delhi-NCR,’ which stated that secondary particulates, formed out of gases emitted by primary sources like vehicles and biomass, contributed significantly to pollution.
“The atmospheric chemistry within IGP (Indo-Gangetic Plain) airshed significantly amplifies particulate pollution through secondary aerosol formation,” it added.
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“It has been recognised that Delhi-NCR’s air quality is influenced by both local sources and transboundary effect of regional movement of pollution across the airshed.”
The report underlined that Delhi’s pollution profile shifts drastically between seasons. While dust from roads and construction is the dominant pollutant in summer (27%), winter see a surge in combustion-related emissions. The report identified secondary particulates from gaseous emissions as the largest component of winter pollution (27%). These particles are not emitted directly, but formed through chemical reactions of precursor gases emitted by vehicles and industries.
Transport emerged as the primary source, contributing 23% to the winter pollution load. Experts pointed out that beyond tailpipe exhaust, the sector’s impact is aggravated by non-exhaust emissions such as brake wear, tyre abrasion, and resuspended road dust. The “daily influx of vehicles from outside the city” and traffic congestion leading to inefficient combustion were cited as critical factors.
Meanwhile, biomass burning and municipal solid waste, residential heating, and crop residue burning, account for around 20% of PM2.5 concentrations in winter, it said. The report also noted that while crop residue burning is concentrated in a 30-day window in October-November, it can contribute up to 40% of Delhi’s pollution load during peak harvest season.
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However, the experts cautioned that the severe winter spikes are not solely due to increased emissions, but driven by meteorology. The report describes a “lid” effect where low wind speeds and a shallow Planetary Boundary Layer (PBL) trap pollutants close to the ground, preventing dispersion.
Sophiya Mathew is a Correspondent at The Indian Express, based in New Delhi. She joined the Delhi bureau in 2024, and has specialization in Integrated Multimedia Journalism from the Asian College of Journalism (ACJ), Chennai.
Professional Background
Core Beats: Her reporting is primarily focused on the Environment and Education.
Specialization: She has gained recognition for her ground-level reporting on the Yamuna floodplains and the socio-economic challenges faced by those living on its banks. She also focuses on the disparities in Delhi's education system, ranging from elite private schools to government institutions and refugee education.
Recent Notable Articles (December 2025)
Her recent work has been heavily centered on Delhi's severe winter pollution crisis and the government's regulatory responses:
1. The Air Pollution Crisis
"A tale of two cities: Delhi govt schools choke in bad air, private classrooms set up air filters" (Dec 20, 2025): A high-impact feature contrasting the "Clean Air Bubbles" in elite schools with the reality of government school students who are exposed to an equivalent of 17 cigarettes a day due to outdoor exposure.
"Delhi sees season's worst air day, second worst December AQI in nearly a decade" (Dec 15, 2025): An analytical report on the meteorological patterns trapping pollutants in the NCR.
"Delhi bans non-BS VI vehicles from outside: Why curbing vehicular pollution is key" (Dec 17, 2025): Explaining the science behind targeting specific vehicle vintages to lower particulate matter.
2. Enforcement & Regulations
"No fuel at pumps in Delhi without valid PUC certificate from December 18" (Dec 17, 2025): Breaking the news on the environment ministry's strict "No PUC, No Fuel" policy.
3. Education Policy
"Law to regulate school fee in Delhi risks becoming procedural, say parents" (Dec 13, 2025): Investigating the loopholes in the new Delhi School Education (Transparency in Fixation and Regulation of Fees) Bill, 2025.
"Monsoon Session: Private school fee regulation Bill cleared after four-hour debate" (Aug 9, 2025): Covering the legislative passage of the controversial fee hike regulation.
Signature Style
Sophiya is known for her observational depth. Her reporting often includes vivid details from school corridors, hospital waitlists, or the banks of the Yamuna to illustrate how policy failures affect the city's most vulnerable residents. She is a frequent expert guest on the 3 Things podcast, where she explains the complexities of Delhi’s environmental laws.
X (Twitter): @SophiyaMathew1 ... Read More
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