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Eye on tackling air pollution, Delhi govt ties up with IIT-Madras to study “smog-eating” coatings on roads

The project, funded by the Delhi government and led by Professor Somnath C Roy of IIT Madras, will begin with laboratory testing before moving to field trials in Delhi, though the areas for those trials are yet to be decided.

5 min readNew DelhiMar 23, 2026 06:32 AM IST

Eye on tackling air pollution: Govt ties up with IIT-Madras for study on ‘smog-eating’ coatings on roads

The experiment is part of a six-month collaboration between the Delhi government and IIT Madras.

Can “smog-eating” photocatalytic coatings, when applied on roads, pavements, and tiles, dismantle key air pollutants and clean Delhi’s foul air? This is what scientists at the Indian Institute of Technology (IIT) Madras are researching, as they attempt to simulate the Capital’s toxic air.

The experiment is part of a six-month collaboration between the Delhi government and IIT Madras, formalised on March 13, to test whether “smog-eating” photocatalytic coatings on public spaces could reduce pollutants such as nitrogen dioxide (NO₂) and volatile organic compounds (VOCs), both key drivers of urban air pollution.

The project, funded by the Delhi government and led by Professor Somnath C Roy of IIT Madras, will begin with laboratory testing before moving to field trials in Delhi, though the areas for those trials are yet to be decided.

“Based on our preliminary results, we will make recommendations, and the Delhi government will decide in which areas exactly the pilot will be conducted,” Roy said.

Environment Minister Manjinder Singh Sirsa said the study would help determine whether such coatings could be applied widely across the city, on roads, buildings, and other infrastructure. “Through this study, we aim to find the best, long-lasting, and affordable ways to put ‘smog-eating’ coatings on roads, buildings, and city surfaces. It can work in our favour if the study can provide evidence based findings that such coatings or materials can cut NO₂ & other pollutants,” Singh said.

To recreate real-world conditions, the team plans to build a controlled smog environment. “We will create smog in our laboratory,” Roy added. “Using real data from Delhi including traffic patterns, pollution levels, we will recreate those conditions and study how the material performs.”

The idea is to reduce a vast, unpredictable urban problem into something measurable. To achieve it, the team will simulate different pollution scenarios using existing data on nitrogen oxide levels collected from government sources and public pollution displays.

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“We will prepare smog samples based on real-world data,” Roy said. “Then we will test how long it takes for ‘smog-eating’ surfaces to bring pollution down to safer levels.”

At the centre of the experiment is the evaluation of titanium dioxide (TiO₂)-based surfaces in dismantling air pollutants. TiO₂ is a material that reacts under sunlight.

“When sunlight hits TiO₂, it generates electrons which come up on the surface” Roy said. “These electrons react with pollutants like NO₂ and break them down into simpler, such as nitrogen and oxygen,” Roy said.

The process, Roy explained, is similar to how solar panels work, but instead of producing electricity, TiO₂ drives chemical reactions that dismantle pollutants. “Sunlight alone cannot break these molecules,” he said.

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The government, meanwhile, has framed the project as part of a broader push for scalable, science-driven solutions. “It is essential to find innovative scientific solutions for cleaning Delhi’s air,” said Sirsa.

The Minister also stressed the urgency of finding solutions to tackle pollution that keep pace with the Capital’s growth. “Delhi’s population is growing with urbanisation from nearby areas, expanding our infrastructure rapidly. Our focus, under the leadership of Chief Minister Rekha Gupta, remains on achieving cleaner air for the people, without blanket bans.”

According to the project plan, the study will explore multiple modes of deployment, including mixing TiO₂ into concrete and asphalt, applying it as coatings, and developing panels that can be installed on rooftops or mounted on streetlights, similar to solar panels.

“These panels could directly interact with ambient air”, Roy said. “In the long term, if deployed at scale, especially in high-emission areas, they could have a measurable impact.”

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Importantly, however, the technology is not intended as a standalone fix. “This will be a continuous background process,” Roy said. “It will not replace other pollution-control measures. It will work alongside them.”

Inside the smog chamber, researchers will test the material under different lighting conditions (full sunlight, reduced sunlight, and even street lighting) to understand how it performs in Delhi’s varied conditions. This is particularly relevant given how severely smog can limit sunlight in the city. “We know that during peak smog, sunlight intensity drops significantly, so that is part of what we will test,” he added.

“In an open environment, the process will take longer,” Roy said. “In the lab, we can force gases to interact with the surface. In the real world, air is constantly moving.”

Wind, he said, will therefore be a key variable in later phases of the study. “Wind does not affect the material itself,” Roy noted. “But it carries pollutants away and brings new ones in. So the interaction is constantly changing.”

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Apart from wind, there exist other challenges as well. Dust, a constant in Delhi, can settle on treated surfaces, reducing their effectiveness. “Dust can block both light and contact with pollutants,” Roy said. “So periodic cleaning, perhaps once a month, will be necessary.”

The material itself, however, is stable and relatively inexpensive. “TiO₂ is chemically very stable like sand..It is commercially available and does not significantly increase construction costs,” Roy said.

Before costs can be estimated, though, the study will first examine how much of the material is needed, for example, how it can be mixed with road tar or applied as coatings.

“We first need to optimise the concentration of TiO₂,” Roy said. “Only then can we calculate cost.”

Vidheesha Kuntamalla

Vidheesha Kuntamalla is a Senior Correspondent at The Indian Express, based in New Delhi. She is known for her investigative reporting on higher education policy, international student immigration, and academic freedom on university campuses. Her work consistently connects policy decisions with lived realities, foregrounding how administrative actions, political pressure, and global shifts affect students, faculty, and institutions. Professional Profile Core Beat: Vidheesha covers education in Delhi and nationally, reporting on major public institutions including the University of Delhi (DU), Jawaharlal Nehru University (JNU), Jamia Millia Islamia, the IITs, and the IIMs. She also reports extensively on private and government schools in the National Capital Region. Prior to joining The Indian Express, she worked as a freelance journalist in Telangana and Andhra Pradesh for over a year, covering politics, rural issues, women-centric issues, and social justice. Specialisation: She has developed a strong niche in reporting on the Indian student diaspora, particularly the challenges faced by Indian students and H-1B holders in the United States. Her work examines how geopolitical shifts, immigration policy changes, and campus politics impact global education mobility. She has also reported widely on: * Mental health crises and student suicides at IITs * Policy responses to campus mental health * Academic freedom and institutional clampdowns at JNU, South Asian University (SAU), and Delhi University * Curriculum and syllabus changes under the National Education Policy Her recent reporting has included deeply reported human stories on policy changes during the Trump administration and their consequences for Indian students and researchers in the US. Reporting Style Vidheesha is recognised for a human-centric approach to policy reporting, combining investigative depth with intimate storytelling. Her work often highlights the anxieties of students and faculty navigating bureaucratic uncertainty, legal precarity, and institutional pressure. She regularly works with court records, internal documents, official data, and disciplinary frameworks to expose structural challenges to academic freedom. Recent Notable Articles (Late 2024 & 2025) 1. Express Investigation Series JNU’s fault lines move from campus to court: University fights students and faculty (November 2025) An Indian Express investigation found that since 2011, JNU has appeared in over 600 cases before the Delhi High Court, filed by the administration, faculty, staff, students, and contractual workers across the tenures of three Vice-Chancellors. JNU’s legal wars with students and faculty pile up under 3 V-Cs | Rs 30-lakh fines chill campus dissent (November 2025) The report traced how steep monetary penalties — now codified in the Chief Proctor’s Office Manual — are reshaping dissent and disciplinary action on campus. 2. International Education & Immigration ‘Free for a day. Then came ICE’: Acquitted after 43 years, Indian-origin man faces deportation — to a country he has never known (October 2025) H-1B $100,000 entry fee explained: Who pays, who’s exempt, and what’s still unclear? (September 2025) Khammam to Dallas, Jhansi to Seattle — audacious journeys in pursuit of the American dream after H-1B visa fee hike (September 2025) What a proposed 15% cap on foreign admissions in the US could mean for Indian students (October 2025) Anxiety on campus after Trump says visas of pro-Palestinian protesters will be cancelled (January 2025) ‘I couldn’t believe it’: F-1 status of some Indian students restored after US reverses abrupt visa terminations (April 2025) 3. Academic Freedom & Policy Exclusive: South Asian University fires professor for ‘inciting students’ during stipend protests (September 2025) Exclusive: Ministry seeks explanation from JNU V-C for skipping Centre’s meet, views absence ‘seriously’ (July 2025) SAU rows after Noam Chomsky mentions PM Modi, Lankan scholar resigns, PhD student exits SAU A series of five stories examining shrinking academic freedom at South Asian University after global scholar Noam Chomsky referenced Prime Minister Narendra Modi during an academic interaction, triggering administrative unease and renewed debate over political speech, surveillance, and institutional autonomy on Indian campuses. 4. Mental Health on Campuses In post-pandemic years, counselling rooms at IITs are busier than ever; IIT-wise data shows why (August 2025) Campus suicides: IIT-Delhi panel flags toxic competition, caste bias, burnout (April 2025) 5. Delhi Schools These Delhi government school grads are now success stories. Here’s what worked — and what didn’t (February 2025) ‘Ma’am… may I share something?’ Growing up online and alone, why Delhi’s teens are reaching out (December 2025) ... Read More

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