'Make emitters responsible': Thailand's clean air activists


By AFP

Dec 28, 2025

Skyscrapers are seen amidst high air pollution levels in Bangkok, Jan. 20. AFP-Yonhap

BANGKOK — A finance specialist who struggled after running in smog and a doctor who fears for the health of his children are among the activists spearheading landmark air pollution legislation in Thailand despite political uncertainty.

Each winter, large parts of Thailand are plagued by haze caused by weather patterns, seasonal burning, vehicle exhaust and industrial emissions.

Years of efforts to tackle the problem, including work-from-home policies and rules on crop stubble burning, have done little to alleviate the issue.


Now, there is a glimmer of hope for fresh action in the form of the Clean Air bill, which would enshrine the right to breathable air, tax emitters and offer public information on the sources of pollution.

Wirun Limsawart, who has helped lead the push for the measure as part of the Thailand Clean Air Network (CAN), grew up in southern Nakhon Si Thammarat.

But it wasn't until he returned to Thailand in 2018 after a decade abroad that he realised the scale of the country's pollution problem.

He began to worry about the impact of the dirty air on his three children.

"It made me question my role as an anthropologist and a doctor," he told AFP.

"What can I do?"

Medical anthropologist and physician Dr. Wirun Limsawart, one of the co-founders of Thailand Clean Air Network poses at Thailand's Parliament complex in Bangkok. AFP-Yonhap

The son of a seamstress and a mechanic, Wirun was a straight-A student who studied at one of Thailand's top medical schools.

"My parents always showed me what it meant to genuinely care for others in their work, so that kind of embedded in me," the 49-year-old said.

"I chose a career path that allowed me to help people."

His life has been marked by illness.

In his early twenties, Wirun collapsed on a bus and was diagnosed with a brain tumour.

After chemotherapy and years of follow-up tests, the experience deepened his desire to better understand patients.

"My role was switched to become a patient... I wanted to genuinely understand patients from a doctor's perspective."

After eight years as a general practitioner in some of Thailand's poorest and most remote regions, he obtained a master's degree and PhD in anthropology at Harvard University.

He now works at the Ministry of Public Health as an anthropological doctor, blending medical research with studying human behaviour.

'My problem, too'

Wirun's pollution worries led him to a panel discussion in Bangkok on the issue in 2019, and the conversations evolved into CAN, which has spent several years advancing clean air legislation.

More than 20,000 people backed the group's call for action — surpassing the threshold for public-initiated legislation — and a draft bill passed the Thai parliament's lower house in October.

"We need to make emitters responsible," Wirun said.

But that goal is facing a new hurdle after Thailand's prime minister dissolved parliament this month, putting the bill on hold.

Still, the measure could be brought back after general elections early next year, if there is political will, according to Weenarin Lulitanonda, CAN's co-founder.

"In Thailand, and particularly in the very highly uncertain political environment, one of the things that Thais are certain of is a huge amount of uncertainty," she said.

"Right now, honestly, it's anyone's guess. We really don't know until general elections are held."

An outdoor run in 2018 drew Weenarin into clean air activism. The experience left her with a piercing headache she later learned was caused by Bangkok's seasonal smog.

More than 10 million people required treatment for pollution-related health problems in Thailand in 2023, according to the health ministry.

Weenarin had previously lived in New Zealand and never worried about air quality, but the more she looked into the issue, the more she was determined to do something about it.

"How is it possible that (in Thailand) someone has no information about what they are breathing?" she said, recalling the question that pushed her into activism.

Having studied finance and worked at the World Bank, Weenarin began contacting experts to understand the problem before helping establish CAN.

She said her motivation is simple: "If there were an alternative to breathing, I wouldn't care."

Clean-air reforms rarely start with governments or businesses, Weenarin said, and she worries too few Thais see the crisis as their problem.

"Don't vote for anybody who doesn't have clean air legislation as a key political manifesto and a commitment ... follow them, become the political watchdog that we all need to be," she said.

She is determined to keep fighting though, so "enough Thais wake up and say this is my problem, too."

 

Research team develops EPICC air quality model for complex pollution problems

Improves accuracy of simulating PM₂.₅ and ozone

Institute of Atmospheric Physics, Chinese Academy of Sciences

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image: 

The Emission and Atmospheric Processes Integrated and Coupled Community (EPICC) model is openly shared with the atmospheric research community.

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Credit: EPICC model group

A large Chinese research team has developed an air quality model called EPICC (Emission and atmospheric Processes Integrated and Coupled Community Model) that demonstrates improved accuracy in its representations of ozone and particulate matter with a diameter of 2.5 micrometers or less.

The working group's paper is published in the journal Advances in Atmospheric Sciences on December 20, 2025. This article also introduced a new way of collaboration, where the research is credited to a "working group" as a whole instead of individual researchers.

For a long time, the development of air quality models in China has been done by individual researchers or small teams. This way of working has limited overall progress. The researchers created the "EPICC Model Working Group" credit system for the EPICC project, aiming to solve this collaboration problem. This establishes a new model of open source, shared, and cooperative development, providing a system that allows multiple teams to work together efficiently. The successful development of the EPICC model version 1.0 was a collaborative effort by a Model Working Group consisting of 59 researchers from 13 institutions, including the Institute of Atmospheric Physics (Chinese Academy of Sciences), Tsinghua University, and Peking University.

“The development and open-source sharing of this model is a key step for China, moving from following international leaders to running alongside them and even taking the lead in this field. More than just a scientific tool, the working group model offers a ‘China solution’ that other research areas around the world facing similar collaboration challenges can learn from,” explains the EPICC Model Working Group.

The EPICC model is a 3D tropospheric chemistry transport model. Scientists use tropospheric chemistry transport models to study how air pollution and gases move about in the lower atmosphere. These models help scientists better understand pollution and climate change. They are essential scientific tools for pollution control, using numerical simulations to show how pollutants form, move, and settle.

Because of its rapid socioeconomic develop and urbanization, China has become one of the most polluted regions in the world. The presence of coal smoke pollution, acid deposition, photochemical smog, and haze weather all impact China today.

The tropospheric chemistry transport models were first developed in the 1970s. These models have undergone many changes since that time. Today, the models are used to demonstrate differing levels of simulation capability and each is endowed with unique strengths. “Currently, the leading international models are mostly developed in the United States. While these laid the foundation for the field, they aren't always a perfect fit for the complex air pollution characteristics found in China,” explains the EPICC Model Working Group. Scientists in China have realized that creating an open-source model framework is the most efficient approach to enhancing simulation capabilities. 

In 2017, the National Key Scientific and Technological Infrastructure project “Earth System Numerical Simulation Facility” (Earth-Lab) in China was launched. This project provided a regional high-precision simulation system for air pollution, aimed to greatly enhance current levels of high-resolution simulation technology and capacity. It catered to scientific research and application needs focused on the regional environment. In 2021, the National Natural Science Foundation of China funded the “Integrated Research on Simulation, Forecast, and Prediction of the Air Pollution Complex in China.” This project, together with EarthLab, developed the Emission and Atmospheric Processes Integrated and Coupled Community (EPICC) model version 1.0. The EPICC model integrated recent achievements in key physical and chemical processes from the joint major research program called “Formation Mechanisms, Health Effects, and Mitigation Strategies of Air Pollution Complex in China.” 

The EPICC model uses a scientific, modular structure with a standard version control system and a "plug-and-play" design. It includes key physical and chemical processes, such as manganese-catalyzed sulfate chemistry, multiple ways nitrous acid is formed, and interactions between aerosols, clouds, and sunlight. Performance tests show that the EPICC model significantly improves the accuracy of simulating PM₂.₅ (particular matter with a diameter of 2.5 micrometers or smaller) and ozone. It effectively fixes issues found in traditional models, which often underestimated sulfate levels and overestimated summer ozone levels.

The EPICC Model Working Group hopes this model can be useful in regions beyond China. “This model can provide a more effective decision-making tool for China and other rapidly developing countries facing similar complex air pollution problems,” they say.

The EPICC model source code and standard input files can be downloaded from The Earth System Science Numerical Simulator Facility Community Data Portal (https://earthlab.iap.ac.cn/en/index.html).

The research is funded by the National Natural Science Foundation of China and the National Key Research Development Program of China.

 

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Journal

Advances in Atmospheric Sciences

DOI

10.1007/s00376-025-4384-y 

Article Title

Description and Evaluation of the Emission and Atmospheric Processes Integrated and Coupled Community (EPICC) Model Version 1.0

Article Publication Date

20-Dec-2025

 

Feedback loops accelerate warming, other atmospheric changes in Arctic

Oil-field emissions reshaping regional atmospheric processes, researchers report

Penn State

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image: 

This image, taken from the aircraft King Air — the left wing is visible at the bottom right, shows an open lead and the overlying nascent clouds commonly referred to as sea smoke. Sea smoke forms when extremely cold, dry Arctic air moves over comparatively warmer open water in a lead. The resulting intense evaporation saturates the air just above the surface, and as this warm, moist air mixes with the frigid overlying air, water vapor condenses into tiny droplets that rise as swirling, steam-like plumes. 

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Credit: Courtesy of CHACHA research team

UNIVERSITY PARK, Pa. — The climate is changing and nowhere is it changing faster than at Earth’s poles. Researchers at Penn State have painted a comprehensive picture of the chemical processes taking place in the Arctic and found that there are multiple, separate interactions impacting the atmosphere.

Using two instrumented planes and ground-based measurements from a two-month long field campaign to compare chemical processes in two regions in the Arctic — and the largest oil field in North America — to surrounding areas, researchers made three discoveries. The findings were: openings in the sea ice — called leads – significantly influence atmospheric chemistry and cloud formation; emissions from the oil field measurably alter regional atmospheric composition; and together, these processes contribute to a feedback loop that accelerates sea-ice melt and amplifies Arctic warming.

The research was recently published in the Bulletin of the American Meteorological Society. The work was part of a larger multi-institutional project called CHemistry in the Arctic: Clouds, Halogens, and Aerosols, or CHACHA. Led by five institutions, CHACHA examines chemical changes that occur as surface air is swept into the lower atmosphere, resulting in interactions among water particles, low clouds and pollution.

“This field campaign is an unprecedented opportunity to explore chemical changes in the boundary layer — the atmospheric layer closest to the planet’s surface — and to understand how human influence is altering the climate in this important region,” said Jose D. Fuentes, professor of meteorology in the Department of Meteorology and Atmospheric Science and corresponding author of the paper. “The resulting datasets are producing an improved understanding of the interactions between sea-spray aerosols, surface-coupled clouds, oil field emissions and multiphase halogen chemistry in the new Arctic.”

To study the chemistry of the boundary layer of the Arctic, researchers sampled air over snow-covered and newly frozen sea ice in the Beaufort and Chukchi Seas, over open leads and across the snow-covered tundra of the North Slope of Alaska, including the oil and gas extraction region near Prudhoe Bay. The campaign was conducted out of Utqiaġvik, Alaska, between February 21 and April 16, 2022, shortly after the polar sunrise — a period of continuous sunlight following two months of darkness — when the increased UV rays intensify the chemical changes at the surface and in the lower atmosphere.

Researchers found that leads — ranging from a few feet to a few miles wide — created intense convective plumes and cloud formations, while lofting potentially harmful molecules, aerosol pollutants and water vapor — all things that can contribute to warming the climate — hundreds of feet into the atmosphere. These processes accelerated sea-ice loss by forcing even more convection and cloud formation, which increased moisture and heat transfer and led to the formation of even more leads, Fuentes said.

The team identified another feedback loop on land, with chemicals found in the saline snowpacks along the coast reacting with the emissions from the oil field. During the CHACHA campaign, researchers specifically observed bromine production along saline snowpacks — a phenomenon unique to polar regions. These bromine molecules rapidly depleted ozone in the boundary layer, creating another feedback loop that allows more of the sun’s rays to reach the surface, warming the snowpacks and releasing more bromine.

Additionally, during the field campaign, researchers found massive boundary layer changes over the Prudhoe Bay oil fields. Gas plumes from the extraction area reacted in the lower atmosphere, acidifying the air mass and producing harmful substances and smog, Fuentes said. They also found that halogens react with oil field plumes to create free radicals, which then form more stable substances that can travel long distances. Fuentes said these substances can contribute to regional environmental changes.

Fuentes said CHACHA researchers are now investigating how these reactions affect the broader Arctic environment, including the formation of smog plumes that, despite occurring in an otherwise pristine region, reach pollution levels comparable to those found in major urban areas such as Los Angeles. For example, nitrogen dioxide levels reached about 60-70 parts per billion, levels associated with the noxious gases blamed for urban smog.

The next steps, researchers said, involve creating datasets that numerical modelers can use to better understand how global climate may evolve as a result of these localized factors in the Arctic.

Other CHACHA team members were from Stony Brook University, the University at Albany, University of Michigan and University of Alaska Fairbanks. This research was funded by the U.S. National Science Foundation.

At Penn State, researchers are solving real problems that impact the health, safety and quality of life of people across the commonwealth, the nation and around the world.

For decades, federal support for research has fueled innovation that makes our country safer, our industries more competitive and our economy stronger. Recent federal funding cuts threaten this progress.

Learn more about the implications of federal funding cuts to our future at Research or Regress.

Some key researchers and staff who deployed to Utqiaġvik, Alaska, for the CHACHA campaign are seen with two research aircraft, the University of Wyoming King Air (left) and Purdue University Beechcraft Duchess Airborne Laboratory for Atmospheric Research.  Shown in front of the aircraft are pilots and engineers from the University of Wyoming and scientists from University of Michigan, the University at Albany, Penn State, Stony Brook University and University of Alaska Fairbanks.  

Credit

Courtesy of CHACHA research team

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Journal

Bulletin of the American Meteorological Society

DOI

10.1175/BAMS-D-24-0192.1 

Method of Research

Observational study

Subject of Research

Not applicable

Article Title

Overview of the Chemistry in the Arctic: Clouds, Halogens, and Aerosols (CHACHA) Field Campaign

 

California Protects Blue Whales and Blue Skies With Historic State Law

NOAA file image

Published Dec 16, 2025 4:33 PM by Protecting Blue Whales and Blue Skies

 

In October, California Assembly Bill 14, “Coastal resources: Protecting Blue Whales and Blue Skies Program” (AB-14) was signed into law, making California the first state in the country to strengthen a longstanding voluntary effort to reduce air pollution and risks to endangered whale populations off California’s coast by reducing speeds of large ocean-going vessels.

 Air pollution is one of the biggest environmental threats to human health, linked both to increased risk of chronic diseases and mortality. In California, due to a combination of factors, many cities and counties rank among the United States’ worst for air quality, and emissions from ships are a significant contributor.

Whale-ship collisions are a top risk to endangered whales globally and California is one of the few places with protection measures in place. Now, thanks to AB 14, spearheaded by Assemblymember Gregg Hart, protections will expand as the Protecting Blue Whales and Blue Skies Program (BWBS) becomes a statewide voluntary program, with California’s Ocean Protection Council as a new partner.

Why?

California is a hotspot for both global trade and biodiversity and one of the largest economies in the world. And California’s major ports— including the Ports of Los Angeles, Long Beach, Oakland, Hueneme, and San Diego — are major hubs for international trade and major entry points to the U.S. market, accounting for about 40% of all containerized imports. Global trade and the container, bulk, vehicle carrier, and tanker ships that make it possible are critical to California and to global economies.

The goods transported by ocean freight have significantly lower carbon footprints than those moved by air. These ships, however, are also one of the top threats to whales around the world and remain a significant source of air pollution for many communities. Onshore prevailing winds push ship exhaust into California coastal communities, where cargo ships can account for 50% or more of counties’ air pollution (notably, smog-forming nitrogen oxides (NOx)). Commercial shipping is also a significant source of ocean noise pollution, which can disrupt marine animals’ capacity to communicate, navigate and forage.

However, when large vessels slow from baseline speeds of 15 knots to 10 knots or less, the risk of a fatal strike to whales is reduced by approximately 50%. Air pollution and emissions are also reduced by almost a third, and underwater radiated noise pressure is significantly lowered.

Recognizing the array of environmental benefits offered by Vessel Speed Reduction (VSR), for the past decade BWBS has verified and encouraged global shipping lines’ cooperation with voluntary, seasonal VSR requests for transit speeds at whale-safer 10 knots within set zones from May to December during peak endangered whale and smog seasons. The BWBS partners and VSR zones have consistently grown over time, from Point Conception and the Port Complex of Los Angeles and Long Beach to Dana Point to Point Arena including all 5 national marine sanctuaries off California.

From 2014 to 2024 the program resulted in:

• 1,596,008 nautical miles of whale-safer transits
• 5,900 tons of smog-forming NOx emissions avoided
• 200,000 metric tons of regional greenhouse gas emissions avoided
• 4.1-decibel reduction in participating vessels source levels
• 50% reduction in fatal ship strike risk

In 2022, to help drive awareness around and support for responsible shipping, the program opened to ambassadors — entities that import/export or work with participating shipping lines. There are now 31 ambassadors, from leading brands like Patagonia, Peak Design, Nomad, Huffy, Santa Cruz Bicycles, Deckers Brands, Toad&Co and Sonos, to the Port of Oakland and Port of Hueneme, to logistics and freight forwarding companies including JAS Worldwide, The Block Logistics and ShipCo Transport, to emissions capture and control companies like STAX Engineering.

What’s Next?

The existing program covers key transits and shipping lanes for vessels transiting up and down a large portion of coast, with Ventura, Santa Barbara County, and San Luis Obispo County Air Pollution Control Districts, Monterey Bay Air Resources District, and Bay Area Air District partnering in the effort to protect public health. However, all Californians and whales off our coast deserve the same benefits afforded by the program. The same ships and whales protected in the current VSR zones also transit and migrate off San Diego, Morro Bay and the north coast. With AB 14 signed into law, BWBS will expand geographically and expand its impact:

1. It brings an important state agency, the Ocean Protection Council, into the partnership;

2. It authorizes expansion consistent with key program elements to date — voluntary cooperation, verification and quantification of environmental benefits, and acknowledgement of industry leadership; and

3. Program expansion will not interfere with any other existing port-related VSR programs.

Next Steps:

BWBS sincerely values the insights of mariners. BWBS is working to ensure the shipping industry’s operational, safety, and other factors inform program expansion plans alongside protecting air quality and whales.

Industry members are invited to participate in a brief survey, which can be found here. As a second option, interested parties are welcome to also submit feedback here.

For more information on how to sign up your shipping line or join as a program ambassador, email info@bluewhalesblueskies.org, and sign up for our newsletter here.

BWBS partners include: California Marine Sanctuary Foundation; Channel Islands, Chumash Heritage, Monterey Bay, Greater Farallones and Cordell Bank National Marine Sanctuaries; Benioff Ocean Science Laboratory; Ventura, Santa BarbaraCounty,  and San Luis Obispo County Air Pollution Control Districts; Monterey Bay Air Resources District; and the Bay Area Air District. BWBS’ success would not be possible without the strong engagement of our participating shipping lines, ambassadors and their collaborative efforts to protect whales and coastal air quality. Read more here: bluewhalesblueskies.org/impact/

This message is sponsored by BWBS. 

The opinions expressed herein are the author's and not necessarily those of The Maritime Executive.

Delhi Pollution: Mopping Floor With Tap Open!

D Raghunandan | 08 Dec 2025

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It is noticeable that no authority wants to tackle the powerful automobile or construction lobbies, both of whom deny major responsibility and point fingers elsewhere.

Image Courtesy: Wikimedia Commons

Winter is here, bringing with it a heavy pall of pollutant laden smog over Delhi, and on most of Northern India along the Indo-Gangetic plains. During October-February, and especially during the peak pollution months of November-December, governments at the Centre and in Delhi, as well as the media and even the Supreme Court, are suddenly abuzz with policy statements, articles and commentary about air pollution and what needs to be done. From time to time, different scapegoats have been targeted as being primarily responsible, and silver bullet “solutions” are offered.

The problem is, Delhi and other North Indian cities have consistently figured in the top 20 most polluted cities in the world for a long time now. Despite all the fulminations, little has changed. Except that the basic factors involved, the main pollution sources, and the long-term approach required toward a solution, are all reasonably well-known to scientists and decision-makers, but continue to evade strong targeted action due to powerful interests involved. These issues have been addressed repeatedly in these columns but are worth reiterating.

Beyond debating points and academic policy discussions, air pollution has become one of the most pressing, all-India public health crises, some would even say an emergency. About 17 lakh people are estimated to have died all over India in 2022 due to air pollution, and in Delhi, about 17,200 people are estimated to have died in 2023, about 15% of all deaths in the capital that year.

Increasing number of hospitalisations for major respiratory and related cardiac and other ailments, prolonged bouts of asthma including among children, and other serious issues including cancers have been reported in Delhi and elsewhere.

Read Also: Delhi Pollution: One-Size-Fits-All Won’t Work in Transport Sector

Obviously, outdoor workers, construction and other and informal sector workers, street vendors and delivery agents are among the worst affected. Poor and malnourished residents living in congested low-income areas with poor sanitation and hygiene are more vulnerable, along with infants, the elderly and those with pre-existing lung and heart ailments.

Air pollution clearly needs to be addressed on a priority basis. 

Delhi Alone Not Affected

While Delhi has been grabbing the headlines, air pollution is a chronic problem all over the country, to a lesser or greater extent.

Cities and towns in the Indo-Gangetic plains have higher annual average air pollution (classed as ‘Moderate’ to ‘Poor’, corresponding to the multi-parameter Air Quality Index or AQI values of 101-300) than peninsular India and along either coast (‘Satisfactory’ to ‘Moderate’ or AQI 51-200) with many more ‘good’ days than in Northern India.

The Northern plains are characterised by the winter “inversion” in which colder, heavier air laden with pollutants is trapped under a layer of warmer air, taking pollution levels to much higher, more dangerous levels. Strong winds and sea-breezes along the coasts also help blow pollutants away. So, the problem is undoubtedly more serious in the North, including cities such as Guwahati.

The point is that all cities in India have much higher air pollution than the norm, given high population density, power plants, industries and other economic activities, and burgeoning often highly polluting vehicles. Even a quick search on the internet will reveal several surprises among smaller towns and cities with high air pollution levels.

India’s air pollution standards prescribe much higher norms than those in Europe, for example, which are themselves slightly higher than World Health Organisation or WHO norms. India sets a maximum limit for PM 2.5 (particulate matter of size 2.5 microns or 1000th of a millimeter) at 60 μg/m3 (micrograms per cubic metre), usually exceeded many times over, against the European Union’s 20, set to go down to the WHO standard of 10 μg/m3 in 2030.

The EU also has tighter standards for nitrogen dioxide (NO2) and other nitrogen oxides (together NOx), sulphur dioxide (SO2), carbon dioxide and surface ozone (O3). All these latter are serious and very harmful pollutants that are rarely talked about in India, where particulate matter visibly contributing to smog, is focused on almost exclusively.

Particulate matter can be ground down to ever smaller sizes, such as by automobiles moving over road dust. The finest particles, such as PM2.5, can be absorbed into the lung and block pores impairing respiratory functions, whereas even finer particles can directly enter the bloodstream. Particulates also provide a convenient medium for other pollutants to condense around, and also for chemical reactions with gaseous pollutants to form “secondary particulates.”

The National Clean Air Mission launched in 2019 has set moderate targets of reducing PM10 levels by 40% in 131 cities (with poor air quality and one million + cities) by 2025-26,  yet the progress as of 2023 has been poor against even these modest targets. Most funds under this scheme are unused and lapse. The Mission needs complete overhaul with stiffer targets and timelines, and systematic and rigorous monitoring.

False Solutions in Delhi

Over the past several years there has been a really confusing medley of analyses, commentaries and opinions in studies by multiple authorities on pollution sources and solutions, often contradicting each other due to differences in sampling, models and methodologies. As a result, there has been a lack of clarity on major causes, strategies for mitigation, targets and institutional mechanisms. There is a bad need to cut through the confusion and arrive at a broader picture than may inform potential strategies.

The confusion has also driven false narratives, deliberate attempts at obfuscation, and silver bullet solutions that would magically obviate air pollution over Delhi.

For many years, stubble burning by farmers of Punjab and Haryana has been a favourite scapegoat for the media, the Bharatiya Janata Party central government (since both states were governed by Opposition parties) and even the Supreme Court which repeatedly demanded strict penalties and punishment for the banned practice.

Many organisations and commentators, including in these very columns, had clearly shown that stubble-burning took place only over a very short period of a few weeks in October-November to clear left-over stubble after the paddy harvest in preparation for wheat sowing. Studies had shown that even this contributed only around 10% of pollutants over Delhi at worst of times.

Efforts by both Union and state governments to assist farmers in clearing the stubble through machines have been gradually bearing fruit, although much still needs to be done. Government data now shows an almost 90% decrease in stubble burning over five years. In any case, the current severe-to-hazardous pollution levels in Delhi, much after stubble-burning has stopped, should hopefully put an end to this canard.

“Anti-smog guns”or glorified water spraying systems, which could obviously only bring down particulates over a short distance were then pushed by the Delhi government, strongly supported by the SC! Then there was artificial rain by seeding clouds to generate rain, with an estimated 2-3% success rate across all international experiments. All this amounting only to mopping the floor while the tap stays open!

Fight The Real Problem 

Cutting through the clutter, we can arrive at a broad characterisation of sources of pollution in Delhi based on considering data from all the different studies referred to above: about 40-50% vehicles, about 30% road plus construction dust, and the rest from Industries, biomass burning, brick kilns in surrounding areas etc. There could be some quibbling about these numbers, but the broad picture is not likely to change much.

If Delhi targets its vehicular or transportation sector, dust whether from construction or from ambient conditions, and industrial pollutants, coal-fired power plants and brick-kilns in neighbouring states, it would make a major dent in air pollution levels. But even today, the media reports that the Prime Minister’s Office is interested in yet another source apportionment study. There are no mystery pollutants to be unveiled!

It is noticeable that no authorities want to tackle the powerful automobile or construction lobbies, both of whom deny major responsibility and point fingers elsewhere. Press reports of a recent meeting in the Municipal Corporation of Delhi (MCD) state that discussions revolved around dust, biomass burning, industries in surrounding areas, but no mention of vehicles!

The biggest offenders in biomass burning are not neighbourhoods but the 5 big Waste-to-Energy incinerators, run by private operators on behalf of the MCD, which reportedly burn mostly unsegregated solid waste including plastics at undesirably low temperatures of around 800C and spew out massive quantities of particulates and toxic gases such as furans and dioxins. These WtE (waste to energy) plants continue to operate with “green” signals even from the National Green Tribunal and the SC!

Read Also: Gig Workers Amid Rising Air Pollution

Delhi is overrun with personal vehicles, 13 million for a population of 22 million! Obviously, pollution levels will be high, especially with almost 50% of these conforming only to obsolete BS-III or earlier pollution norms. The only answer is to massively shift passengers from personal to badly needed public mass transit systems. The Delhi Metro is a good contributor to mass transit, catering to about seven million passengers daily.  As of 2024, it is estimated to have taken over 650,000 personal vehicles off the roads. But it is highly gentrified and oriented to the middle-class as regards pricing.

A large number of common people rely on buses for public transport, but Delhi’s buses, currently having about 5300 CNG and 1700 E-buses CNG Buses (about 4000 with DTC and 3000 with cluster buses, including 1700 E-buses. Transport planners project a demand for 15,000 buses, including small E-buses to serve interior roads, with good last-mile connectivity and integration. Delhi’s highly under-utilised surface railway system also cries out for revival and modernisation. Non-motorised transport, including dedicated bicycle tracks and pedestrian walkways, are also needed.

Construction activities require to be strictly regulated to control dust pollution. Another, mostly ignored and forgotten problem is the creeping desertification around Delhi due to the rampant destruction of the Aravalli Hill range for quarrying and real estate, removing the dust-shield the hills provided Delhi and its environs. Unfortunately, even the SC recently went along with the Union government in “redefining” the Aravallis in such a way as will further encourage desertification.

There are many battles to be fought.

The writer is with the Delhi Science Forum and All India People’s Science Network. The views are personal.

Delhi Pollution: One-Size-Fits-All Won’t Work in Transport Sector

Aisha Sheikh , Owais Ibni Hassan | 04Dec 2025

Effective de-carbonisation will depend on targeting the highest-emitting segments, rather than treating all vehicles alike.

Delhi’s chronic air pollution challenges are inseparably tied to how the city moves people and goods. The transport sector is a major and growing source of CO₂ and NOₓ emissions, shaped by a highly unequal mix of vehicle types, fuel technologies, and usage patterns. On one end are high-mileage commercial and freight vehicles running largely on diesel under relaxed emission norms; on the other is a rapidly expanding but still imperfect transition toward electric mobility, especially in the last-mile delivery segment. In what follows, we explain how different vehicle categories contribute to Delhi’s emissions profile and argue that effective de-carbonisation will depend on targeting the highest-emitting segments, rather than treating all vehicles alike.

Commercial vehicles (CVs) are the dominant contributors to CO₂ emissions in Delhi, accounting for over 60–70% of annual transport-related emissions. Though they represent a smaller portion of the fleet, CVs (defined here to include tempos, trucks, mini buses, pick-up lorries, and goods carriers) operate longer hours, travel greater distances, and typically run on diesel, which has a higher emission factor than petrol. Many of these vehicles continue to operate under relaxed regulatory norms such as BS III and exhibit lower fuel efficiency. This operational profile explains their disproportionately high emissions footprint.

The Electric Vehicle Policy (2020), which mandates 100% electrification of delivery fleets by 2025, has led to a noticeable shift from petrol to electric vehicles in the two-wheelers last mile delivery segment,

Commercial vehicles are also the leading emitters of NOx, followed by diesel buses. Within the broad category of commercial vehicles (CVs), heavy-duty vehicles (HDVs) are likely the dominant contributors to NOₓ emissions. These vehicles are typically long-haul trucks powered by older diesel engines—combine high engine loads, poor real-world emission control, and long annual vehicle kilometers travelled, resulting in disproportionately high NOₓ output.

The large magnitude of freight-based truck movement in Delhi is driven by a host of geographic, infrastructural and economic reasons. Delhi is a logistics hub of North India, sitting at the intersection of a series of national highways affording fast and convenient road connectivity. It connects Punjab, Haryana, Uttar Pradesh and the broader NCR region making it a transit node for goods moving across North India.

Estimates suggest that about three quarter of fruits and vegetables and almost half of fuel, iron and steel and foodgrains destined for other states traverse through Delhi (Goel and Guttikunda 2015). However the thrust for electrification of HDT (heavy duty trucks) has been neglected in policy design. For example, the Faster Adoption and Manufacturing of (Hybrid &) Electric Vehicles subsidy programme coverage in the second phase extends to two and three-wheelers, car and buses, but excludes HDT’s (Ministry of Heavy Industries 2021).

HDT’s have lagged in the transition to zero emissions both in terms of market development and policy support, leaving a significant policy gap that must be addressed. (ICCT 2024).

Emissions from private cars, by contrast, are volume-driven. Their per-vehicle emission load may be moderate, but the sheer size of the fleet, combined with rising vehicle kilometers traveled and private vehicle dependency—makes them a significant and growing contributor. This underscores the need to curtail car volumes and usage, through demand-side interventions like improved public transport and instruments like congestion pricing.

Emissions reduction strategies must prioritise high-mileage, high-emission segments, especially commercial freight and older diesel vehicles, which have a disproportionate impact on urban air quality. For Delhi to achieve sustained gains in both air quality and climate outcomes, regulation must evolve to reflect real-world vehicle usage.

The writers are researchers having interests in energy economics, transport economics and clean energy. They can be reached at: aiha2400869@st.jmi.ac.in and owaisibnihassan@gmail.com.