Kerala’s Silent Crisis: Old Diesel Vehicles, Pollution, and the Need for Sustainable Action

By Safder Machilakath, Principal Consultant at Uru Consulting, Calicut

Yesterday, as Kerala celebrated Eid ul-Fitr on March 31, 2025, the streets buzzed with families traveling to visit friends and relatives. Amid the festive spirit, I noticed a troubling pattern while stuck in a traffic block: 6 out of 10 vehicles around me were diesel cars registered in other states, predominantly Toyota Innovas and Fortuners. A closer look revealed these vehicles were at least 7 years old, their model styling betraying their age. This isn’t just a random observation—it’s a red flag for Kerala’s environmental future, one that demands urgent attention from both the public and the government.

The Bigger Picture: Metro Cities and Kerala’s Looming Challenge

Kerala may feel like a single, sprawling city with its dense population and interconnected towns, but its environmental sensitivity sets it apart. The state’s lush terrain and biodiversity are at risk as urbanisation accelerates, especially with upcoming national highway projects that will likely speed up this process. These highways, while boosting connectivity, will also increase traffic density—particularly from old, fossil fuel-powered vehicles like the ones I saw. A 2020 study published in Renewable and Sustainable Energy Reviews highlights the environmental toll of diesel vehicles, noting that they emit 22% more CO2 per liter than petrol vehicles and contribute significantly to particulate matter (PM) pollution, with older diesel engines (pre-BS-IV standards) emitting up to 50% more PM2.5 than newer ones. In India, transportation accounts for 12% of energy-related CO2 emissions, a figure projected to double by 2050 if unchecked, according to the International Energy Agency.

Metro cities like Delhi are already grappling with this crisis. Delhi, often dubbed one of the world’s most polluted capitals, has seen vehicular emissions become the top polluter despite measures like the largest CNG program for public transport, phasing out 10-year-old diesel and 15-year-old petrol vehicles, and introducing Bharat Stage VI standards. A 2024 analysis by the Centre for Science and Environment (CSE) reveals that explosive motorization and congestion are undermining these efforts, with vehicles still contributing 70% of local PM2.5 in Delhi. The city’s air quality index (AQI) often spikes to “Severe” (301–400) during winter months, driven by factors like stubble burning and vehicular emissions. In response, Delhi has rolled out new policies: a ban on coal use in industrial and domestic units in the National Capital Region (NCR) starting January 2023, restrictions on non-destined trucks, and a push for electric buses, with plans to replace all CNG buses with electric ones post-2020. Yet, the CSE notes that inadequate public transport and last-mile connectivity continue to drive private vehicle use, exacerbating the pollution burden.

Kerala, while not yet at Delhi’s level, is on a dangerous trajectory. The influx of old diesel vehicles—many of which are likely being “dumped” into Kerala as other states tighten regulations—poses a future burden we can’t ignore. These vehicles, often over 7 years old, lack modern emission controls and contribute disproportionately to PM2.5 and NOx emissions, which are linked to respiratory diseases and premature deaths. With national highways set to accelerate urbanisation, Kerala’s air quality could deteriorate rapidly if we don’t act now.

A Lesson from Uru: Sustainability Starts Small

At Uru Consulting, we’ve learned that sustainability isn’t just a buzzword—it’s a choice, often born from necessity. In our early days as Zeros and Ones Architectural and Engineering Consultants, starting in 2015, the four of us—myself, Siyad, Shabeeb, and later Safwan—shared a single vehicle to commute to our 90sqft office in Ramanattukara, Calicut. We’d meet at a common spot and ride together, rotating vehicles among us. It started as an expense-reducing strategy; with each of us taking just ₹1000 a month, every rupee mattered. But after 2018, we turned this into a policy, not just to save money, but to live our values—a minimal, sustainable business that treads lightly on the planet. That small act of carpooling cut our fuel use, reduced emissions, and reminded us that change begins with the choices we make every day. If a small firm like ours can do this, imagine the impact if every Keralite made similar choices.

Kerala’s Unique Challenge: A Call for Local Action

Kerala’s government must take proactive steps to address this growing threat. First, we need stricter regulations on old vehicles. Delhi’s policy of phasing out 10-year-old diesel vehicles should be a model—Kerala could implement a similar scrappage policy, offering incentives for owners to replace old diesel cars with electric or hybrid alternatives. The state’s sensitive terrain demands an optimal vehicle density, not a free-for-all for fossil fuel engines. Second, we must invest in sustainable public transport. Delhi’s struggle with poor last-mile connectivity and unreliable bus services (despite 57.95% of its population living within 400 meters of a bus stop) is a lesson for Kerala. Projects like the Kerala Semi-High Speed Rail are a start, but we need integrated, eco-friendly transport systems—think electric buses, e-rickshaws, and better pedestrian infrastructure—to reduce reliance on private vehicles.

Public awareness is equally critical. As citizens, we must rethink our choices. Carpooling, like we did at Uru, or opting for public transport and walking for short distances can make a difference. The festive season, with its spike in travel, is a reminder of how our habits impact the environment. If 6 out of 10 vehicles in a traffic block are old diesel cars, imagine the cumulative effect on Kerala’s air quality over time. We can’t wait for the problem to become as severe as Delhi’s before we act.

A Critique: Where Are Our Traffic and Environment Consultants?

Kerala’s approach to this issue exposes a deeper systemic failure. Where are our traffic and environment consultants? The state lacks a dedicated civil engineering wing focused on traffic and sustainability. Our civil engineering efforts are fixated on construction—building roads and bridges—while ignoring the broader environmental impact. During my graduation, I presented a seminar on traffic congestion pricing, a concept used globally to reduce urban traffic and pollution by charging drivers for using congested routes. My teachers questioned whether it was even a civil engineering topic, reflecting a narrow mindset that innovation in our field is limited to mixing plastic or footwear waste into concrete. This isn’t innovation—it’s a distraction from the real challenges.

Worse, global consultants often guide our government with little commitment to Kerala’s people. These consultants, parachuted in with generic solutions, fail to grasp the state’s unique socio-environmental fabric. They push policies that might work in Dubai or Delhi but ignore Kerala’s dense, sensitive terrain and cultural reliance on personal vehicles during festivals like Eid. We need local traffic engineers and environmental experts who understand Kerala’s context—professionals who can design solutions like congestion pricing, low-emission zones, or region-specific vehicle scrappage programs. The government must invest in building this expertise, not rely on outsiders who lack skin in the game.

The Way Forward: A Shared Responsibility

Kerala stands at a crossroads. The upcoming national highways will bring growth, but they’ll also bring more vehicles, more pollution, and more strain on our environment. The government must act now—implement strict vehicle age regulations, incentivize electric vehicle adoption, and build sustainable transport infrastructure. At Uru Consulting, we’ve pivoted to sustainability because we believe in designing for the future, not just the present. Our carpooling policy is a small step, but it’s a start. We hope it inspires others to act.

To the people of Kerala: let’s be mindful of the vehicles we use and the impact they have—carpool, walk, or choose cleaner alternatives. To the government: don’t wait for Kerala to become another Delhi. Act now, with local expertise, to protect our state’s future. The beauty of our struggle is that it’s shared—and together, we can build a cleaner, greener Kerala.