Building Low Carbon Cities: The Role of Sustainable Transport Systems

The transport sector accounts for a significant share of global greenhouse gas emissions, making it one of the most critical areas for climate action. As cities grow denser and more populated, the way people and goods move through urban spaces directly shapes air quality, energy consumption, and overall quality of life. Low-carbon transport is not just about swapping petrol cars for electric ones – it involves rethinking entire mobility systems to be cleaner, more efficient, and accessible to everyone. This post breaks down the benefits, technologies, policies, and real-world examples driving the shift toward sustainable urban transport.

What is low-carbon transport? 🔗

Low-carbon transport refers to mobility systems designed to minimize greenhouse gas emissions while maintaining safety, affordability, and efficiency. This includes everything from walking and cycling networks to electric road transport powered by renewables, enhanced public mobility, and the adoption of clean fuels for shipping and aviation. It is a systems-level approach – not a single technology fix – that integrates infrastructure, policy, urban planning, and behavioral change.

The transport sector contributes to 6.7 million premature deaths annually through air pollution, mostly in low- and middle-income countries, while road traffic injuries claim roughly 1.19 million lives each year. Against this backdrop, building low-carbon transport systems addresses both climate targets and urgent public health crises simultaneously.

Benefits of low-carbon transport 🔗

Reduced congestion and improved air quality 🔗

When cities invest in efficient public transit, cycling lanes, and pedestrian-friendly infrastructure, the number of private vehicles on roads decreases. Fewer cars mean less traffic congestion and significantly lower tailpipe emissions. Systems such as metro, tram, bicycle-sharing, and light rail have low carbon emissions and fossil fuel dependency and are integral to sustainable transportation. The direct result is cleaner air for residents and shorter commute times for workers.

Switching from a conventional vehicle to an electric vehicle can reduce an individual’s carbon footprint by an average of 2 tons per year. When such shifts happen at scale across a city, the collective impact on air quality is substantial.

Energy security and economic resilience 🔗

Heavy reliance on imported fossil fuels makes cities and nations vulnerable to price shocks and supply disruptions. Low-carbon transport systems – powered by locally generated renewable electricity – reduce this dependency. By lowering dependence on imported oil, which still supplies nearly half of global transport fuel, countries can reduce exposure to fuel price volatility and supply disruptions.

Transitioning to low-carbon transportation not only curtails energy consumption and greenhouse gas emissions but also stimulates sustainable economic growth. Investments in clean transport infrastructure create jobs in manufacturing, maintenance, technology development, and urban planning – offering long-term economic returns beyond emission reductions.

Public health and equity 🔗

Sustainable transport systems improve access to jobs, healthcare, and education, especially for marginalized communities. Well-planned bus networks, affordable metro systems, and safe cycling infrastructure ensure that mobility is not restricted to those who can afford private cars. Over a billion people worldwide still lack access to an all-weather road, and only about half of the global urban population has convenient access to public transport. Low-carbon transport directly addresses these gaps.

Technological innovations in low-carbon mobility 🔗

Electric vehicles and battery technology 🔗

Electric vehicles (EVs) have moved from niche products to mainstream options at a remarkable pace. Electric cars represented more than 20 percent of all cars sold globally in 2024, and this figure is expected to reach 25 percent – roughly 20 million vehicles – in 2025. Public charging stations have also doubled in the past two years, removing one of the biggest barriers to EV adoption.

The average carbon emissions of electric vehicles in major countries, after production and 250,000 km of driving, are 27 to 71 percent lower than those of conventional fuel vehicles across their entire lifecycle. Advances in battery technology – including solid-state batteries and improved lithium-ion chemistry – continue to extend range, reduce costs, and shorten charging times.

Fuel-efficient public transit and BRT systems 🔗

Modern public transit is becoming smarter and greener. Bus rapid transit (BRT) systems combine dedicated lanes with smart traffic signals to deliver subway-like efficiency at a fraction of the infrastructure cost. Globally, 198 cities now operate BRT systems carrying close to 33 million passengers every day.

Electric and hybrid buses are rapidly replacing diesel fleets in cities worldwide. Intelligent transportation systems use real-time data to optimize routes, reduce wait times, and improve fleet management – cutting fuel consumption and emissions further.

Hydrogen fuel cells and transitional fuels 🔗

Green technology innovations including sustainable aviation fuel, environmentally friendly propulsion systems, and hydrogen fuel cell vehicles offer multifaceted solutions for decarbonizing transport by enhancing energy efficiency and reducing emissions. Hydrogen fuel cells are especially promising for heavy-duty applications – buses, trucks, and long-haul freight – where battery weight becomes a limitation.

Compressed natural gas (CNG) and biofuels continue to serve as transitional fuels, providing immediate emission reductions while infrastructure for fully electric or hydrogen-powered systems is built out.

Policy-driven shift towards sustainability 🔗

Incentives and subsidies 🔗

Government incentives have been a primary driver of low-carbon transport adoption globally. Policy measures such as setting emissions standards, encouraging green transportation and public transit are being implemented worldwide to foster low-carbon transportation infrastructure. Purchase subsidies, tax exemptions, and reduced registration fees lower the upfront cost of EVs, making them competitive with conventional vehicles.

Carbon pricing is a policy tool that internalizes the environmental costs of carbon emissions, creating a financial incentive for businesses and individuals to choose low-carbon transport options. When carbon-intensive options become more expensive, cleaner alternatives naturally gain market share.

Low emission zones and congestion charges 🔗

Several major cities have implemented low emission zones (LEZs) and congestion pricing to discourage high-emission vehicle use in urban centers. London reduced vehicle traffic by 16 percent and journey times by 14 percent within the first three years of implementing its congestion charge. Stockholm and Milan have adopted similar models with measurable success in shifting commuters toward public transit and cycling.

Congestion charging involves imposing fees on vehicles entering certain congested areas, encouraging the adoption of sustainable transportation choices by making them economically competitive.

Infrastructure investments and urban planning 🔗

Effective policy goes beyond pricing – it includes strategic investment in the physical infrastructure that makes low-carbon mobility possible. Dedicated bus lanes, protected cycling networks, pedestrian zones, and comprehensive EV charging networks all require coordinated planning and sustained funding. Cities that have successfully lowered transport emissions typically combine regulation, financial incentives, and infrastructure development into a single, coherent strategy.

Global case studies 🔗

Bogotá’s TransMilenio BRT system 🔗

Bogotá’s TransMilenio system is one of the most studied examples of successful BRT implementation. The BRT system operates across 114.4 km of exclusive lanes, with a fleet of bi-articulated, articulated, and rigid bus units serving 98 routes. The system has received international recognition, including from the World Health Organization and the World Bank, for reducing greenhouse gas emissions in the transport sector.

In February 2023, Bogotá’s integrated transport system recorded over 92 million boardings, with TransMilenio alone accounting for nearly 42 million BRT boardings. The system demonstrates that developing cities can achieve high-capacity, efficient transit without the enormous costs of metro construction.

London’s congestion charge and ULEZ 🔗

London was among the first major cities to implement congestion pricing in 2003. Traffic congestion had worsened to the point that average speeds were comparable to those of horse carts in the nineteenth century before the charge was introduced. The congestion charge, combined with the Ultra Low Emission Zone, has transformed central London’s transport landscape and generated revenue that is reinvested into public transit improvements.

Seoul’s urban transport transformation 🔗

Seoul demolished a principal elevated expressway and replaced it with the restored Cheonggyecheon corridor, with minimal congestion impacts, partly because the city’s new BRT system absorbed former car users. The city also runs a weekly no-driving-day program offering incentives like free parking and tax reductions to participants, which has contributed to measurable reductions in traffic volumes and CO₂ emissions.

India’s progress in low-carbon transport 🔗

FAME scheme and PM E-Drive 🔗

India has emerged as one of the most active developing nations in promoting electric mobility. The country provided incentives under Phase I and II of the Faster Adoption and Manufacturing of Electric Vehicles (FAME) scheme between 2015 and 2024, which were recently expanded under the PM E-Drive Scheme. This latest scheme aims to incentivize the sale of approximately 2.5 million electric two-wheelers and 320,000 electric three-wheelers through subsidies worth an estimated USD 315 million.

The broader PM E-Drive scheme, with an allocation of Rs 10,900 crore, has supported over 28 lakh vehicles by mid-2025, including more than 14,000 electric buses. This multi-segment approach reflects India’s recognition that different vehicle categories need tailored electrification strategies.

Electric bus deployment and charging infrastructure 🔗

Under the PM-eBus Sewa Scheme, launched in August 2023 with Rs 20,000 crore in support, the government aims to deploy 10,000 electric buses through public-private partnerships, with 7,293 e-buses sanctioned across 14 states and 4 union territories by mid-2025.

Charging infrastructure is expanding in parallel. Under FAME II, the government approved a capital subsidy of Rs 800 crore to set up 7,432 EV public charging stations across the country. The government is also developing National Highway EV Corridors with fast charging stations planned every 50 km on major highways.

India’s unique challenges and 2030 targets 🔗

About 75 percent of Indian vehicles are two-wheelers, with only 13 percent being cars – making India’s EV transition fundamentally different from Western models. The three-wheeler segment has been an unexpected success story, with electric three-wheelers capturing over 54 percent of new sales in their category.

India’s 2030 target of 30 percent EV penetration aligns with the global EV30@30 initiative and supports broader climate goals of reducing carbon emissions by one billion tonnes and carbon intensity by 45 percent by 2030, en route to net-zero by 2070. To accelerate progress, NITI Aayog launched the India Electric Mobility Index in August 2025 to track state-level performance across vehicle electrification, charging readiness, and research.

The road ahead 🔗

Building low-carbon cities through sustainable transport is not optional – it is essential for meeting global climate targets, improving public health, and creating livable urban spaces. The good news is that the tools already exist: electric vehicles, smart public transit, cycling infrastructure, congestion pricing, and supportive policy frameworks. What is needed now is the political will and coordinated investment to deploy these solutions at scale.

By 2030, annual passenger traffic is expected to exceed 80 trillion passenger-kilometres – a 50 percent increase over 2015 levels – potentially adding 1.2 billion more cars to roads worldwide. Without a decisive shift toward low-carbon transport, the resulting emissions, pollution, and congestion will be overwhelming.

Every city that invests in sustainable transport today is building resilience for tomorrow. The examples from Bogotá, London, Seoul, and India show that meaningful progress is achievable across different economic contexts and urban scales.

What do you think? Can cities in developing countries leapfrog traditional car-centric development and build transport systems around low-carbon mobility from the start? What role should citizens play in demanding better public transit and cycling infrastructure in their cities?

References

1. https://www.iea.org/reports/global-ev-outlook-2025/executive-summary
2. https://www.un.org/en/desa/transport-transformation-critical-address-climate-change-and-universal-access-safe-affordable
3. https://academic.oup.com/ce/article/8/3/34/7656752
4. https://www.niti.gov.in/sites/default/files/2025-08/Electric-Vehicles-WEB-LOW-Report.pdf
5. https://www.climatepolicyinitiative.org/publication/outlook-of-future-mobility-in-india-with-ev-transition/