Cities & Public ServicesDecember 13, 2023

What is a sustainable city? A circular economy and other emerging characteristics

A sustainable city is one that is created with the intention of reducing negative environmental impacts through urban planning, city management and activities pertaining to energy usage, transportation, use of natural resources, infrastructure, waste management and water.
Avatar Gabby Gelbien

Cities are home to an estimated 56% of the population and this number is growing, with 5 billion people projected to live in urban areas by 2030. In order to plan for this population growth, combined with rising climate issues, aging infrastructure, limited space, waste management complexities and more, cities will need to adapt and manage themselves in a more sustainable manner. 

The concept of a sustainable city was once viewed as a bit of a utopia. In this thriving green ecosystem, the sky is clear of smog and there are more pedestrians and cyclists than cars on the road. Well, as it turns out, we may be closer to achieving this fairytale than we think. 

With cities responsible for about 70% of global greenhouse emissions, there is rising pressure from scientists and government officials to pivot how cities are created, reimagined and operated to be smarter and greener so that we can secure a safe future. But, what does a sustainable city look like? Let’s begin with a definition.

What is a sustainable city?

A sustainable city is one created with the intention of reducing negative environmental impacts through urban planning and city management. Through its activities, a sustainable city addresses social, environmental and economic impacts regarding energy usage, transportation, use of natural resources, infrastructure, waste management and water.

At their core, sustainable cities must be resilient. Whether it’s due to the impact of climate change or the activity of humans, a sustainable city is a place where both citizens and ecosystems can not only co-exist but thrive in the long-term. 

What are 7 characteristics of a sustainable city?

There are many building blocks to making a city sustainable. While most cities today will not possess every one of these characteristics, the goal is to strive for as many as possible in order to achieve carbon neutrality

1. Green space

Green space is a dedicated open space in a metropolitan area – like a park, garden, playground, or public plaza – that is free of the negative impacts of the buildings and modes of transportation that have a harsh impact on the environment.

Green spaces can help the mental and physical health of citizens by being a space for adults and children alike to clear their minds from city noise and encourage recreational activity. They can also improve air quality, reduce noise, enhance biodiversity and regulate extreme temperatures by reducing carbon emission levels in cities. 

One type of green space increasingly being tested out in cities is urban farms. This includes vertical gardens, rooftop farming, community gardens, or farms at schools. Supporting the growth of vegetation in your own city has many benefits, including boosting the local economy, providing locally sourced, healthy food for your community, cutting down on the energy required to ship food around the globe and even boosting community morale by turning underutilized spaces in your city into a beautiful landscape. 

Singapore is one city testing out urban farming and finding great success. With their “30 by 30” vision, they are striving to produce 30% of their food locally and sustainably by 2030. They’re using new and existing landscapes like the ground, the insides of buildings, walls and even rooftops to grow produce and herbs. Because much of their farming is concentrated indoors, growers can control water, temperature and soil conditions to avoid pests and diseases. It also enables them to harvest year-round regardless of the weather. 

2. Circular economy and infrastructure 

A circular economy is an economy that relies on its own resources like food, energy and materials to sustain itself. It embraces the principles of reuse, recycle, reduce, and remanufacture to minimize waste and extend the lifespan of products for as long as possible. Why is this important? 

When we extend and renew the lifespan of materials, we can keep them for longer and avoid using new natural resources. This is in contrast to a linear economy, also known as a “take-make-waste” economy, which uses a fixed amount of resources with a limited lifespan to make products that aren’t used to their fullest potential and become waste. 

Cities play a critical role in promoting a circular economy due to their economic activity, consumption and waste production. Because a circular economy affects all public policies managed by a city,  urban planning with a keen focus on sustainability is critical. Whether it is waste treatment, energy, the purchase of materials, the recycling of urban equipment or building maintenance, it will take the collective teamwork of industries, local players, and stakeholders to create public policies and territorial strategies that foster the growth of circularity practices.

3. Solar panels and renewable energy 

A sustainable city will utilize renewable energy to keep the electricity going in a variety of buildings like schools, offices and government buildings, and even households. Considered one of the most affordable and efficient forms of energy, solar is a powerful contributor to a circular economy due to its unlimited power source: the sun. 

According to the international non-profit, CDP, of the 620+ global cities reported, over 100 now get at least 70% of their electricity from renewable sources such as hydro, solar, wind and geothermal. In fact, Atlanta, Paris and Vancouver have already achieved 100% renewable electricity and are on the path to 100% renewable energy, overall. These cities are paving the way by showing that transitioning to renewable energy is not only something cities want, but are pulling off.

4. New forms of transportation 

Globally, the transportation sector is responsible for 20% of the emissions released into the atmosphere and is the second-largest contributing sector to carbon pollution. Cities are calling for alternative forms of transportation to gas-powered cars, like electric vehicles, hydrogen-powered cars, biking, taking the metro, or simply walking. City planners can do their part in encouraging alternatives to gas-powered cars by providing charging stations for EVs, providing the proper funding for public forms of transportation, or creating suitable streets for bike paths. 

Virtual twin technology is one way to help decision-makers analyze the impact of mobility changes in their territories. When Paris was appointed the 2024 Olympic Games host, their governing body knew they would have to create new transportation routes to help people move quickly from one Olympic location to the next. Dassault Systèmes created a digital twin demo based on Dassault Systèmes’ 3DEXPERIENCE platform on the cloud to visualize the impact of dedicating one of three lanes as a carpool lane and its effects on traffic, air and noise pollution. This demo illustrates how science-based capabilities can help city decision-makers make informed decisions about transportation and mobility options in the city and use these decisions to drive future public policies. 

5. Eco-friendly waste management 

In traditional cities, waste is thrown away and ends up in a landfill where non-biodegradables and inorganic elements take a long time to decompose, hurting the environment. Additionally, outdated or aging sewer systems can easily become overwhelmed with stormwater and cause untreated wastewater to fall into local bodies of water, polluting them. Therefore, cities that wish to be sustainable should increasingly invest in new infrastructure, recycling programs, and composting mandates to break down waste better suited for the environment. 

Additionally, cities can maximize the reuse, recycling and recovery of materials by implementing advanced selective collection, sorting, and treatment systems that allow cities to recover a large amount of potential resources present in waste. By saving raw materials, cities can reduce the environmental footprint and stimulate the local economy by creating job opportunities in the waste management sector. 

6. Water conservation

With climate change accounting for droughts in more severity and frequency, finding new ways to conserve water in cities is more important than ever. Cities can implement water-saving techniques through programs that promote the installation of low-flush toilets, billing users based on the amount of water used, recycling water, and installing more efficient sprinkler systems. They can even install leak detection piping and smart meters that allow citizens to see how much water is being used and where. Some cities are even testing our rainwater harvesting, like Potsdamer Platz in Berlin. Green roofs harvest the city’s annual rainfall and rainwater is used for toilet flushing, irrigation, and fire systems, and any excess water is used to support outdoor waterscapes and natural habitats.

Another city paving the way in water conservation is Copenhagen, Denmark. They’ve introduced incentives and strict regulations for residents and businesses when it comes to water-saving practices. This includes public awareness campaigns that educate the community about the importance of responsible water use and the promotion of water-efficient fixtures and appliances. As a result, the average Copenhagener only uses 26 gallons of water a day. Compare this to the average U.S. citizen who uses up to 80 to 100 gallons a day. 

7. Embracing digitization 

In order to create a city that is resilient and ready for the future, long-term strategies must be put in place with the help of technology. With the help of virtual twin technology, city planners can better understand which parts of the city are most impacted by climate change, simulate various scenarios and anticipate natural disasters before they happen. Additionally, technology can help them collect large amounts of data that can be used to create science-based objectives and meet their sustainability goals. 

Furthermore, digital platforms enable circular economy principles to be applied on a larger scale by improving access to information, managing and tracking materials and increasing transparency. For example, you can use a digital platform to map out empty buildings to avoid new constructions and plan alternative uses of existing ones. Similarly, cities can optimize the use of parking space during the day and night by mapping their usage rates. Digital platforms have even gone as far as revolutionizing waste management by offering powerful tools for optimizing waste collection sorting and recovery. Leveraging real-time data, collection trucks can better communicate between various team members and plan more efficient routes for collecting waste. Over time, all of this data and information can be used by policymakers and stakeholders to instill change and foster the transition to circular economy practices. 

Benefits of a sustainable city

Boosts equality

Low-income communities face challenges like not having access to clean water or healthy food, good-quality housing, safe transportation, water sanitation or energy. All of these components are especially affected by climate change and weather-related disasters. By making sustainable changes to infrastructure, making roads more accessible for walking and cycling, improving public transportation, water sanitation, growing local food, and more, city planners can improve the lives of underserved communities and boost equality. 

Lowers CO2 emissions 

With cities currently contributing 70% of CO2 emissions into the atmosphere, city planners and the citizens who make up these urban hubs play a huge role in doing their part to reduce the amount of CO2 emissions in the atmopshere. All of the components of a sustainable city – alternative energy sources, reduced waste, green spaces, urban farming and more – were created with the intention of reducing the amount of greenhouse emissions put into the air. Even just shifting to one of these activities can make a positive impact on the environment due to how much of the global population resides in urban areas. 

Improved health and wellness

Sustainable activities can greatly improve the health and wellness of the citizens who live there. Those who live in apartments with inadequate insulation or cooling are at risk for heat stroke. Air pollution, storming and flooding can lead to mold and bacteria that greatly affect the lungs. Power outages can lead to food spoilage and stomach viruses. Not having access to adequate green spaces can lead to an increase in obesity and poor mental health. When sustainable measures are put into place and cities are designed for the people who live in them, it leads to healthier and more fulfilling lives for all. 

Reduces energy costs

Renewable energy sources, like solar power and wind energy, contribute to a circular economy and help save money. According to research by Oxford University, ending the use of fossil fuels by 2050 can save the world at least roughly $12 trillion since key green technology costs are predicted to lower drastically as adoption increases. Over the last decade, renewable energy sources have dropped about 10% per year and researchers anticipate the costs continuing to fall. This is not only good news for the environment, but your wallet as well. 

Sustainable cities: Opportunities to get started

Circularity as a response to city challenges

Experts in the field believe circularity is the answer to the challenges cities face. Instead of looking at cities as a collection of isolated issues to address like mobility, architecture and waste management, it’s now considered more effective to collaborate across multiple city industries and departments to gain a holistic view of the challenges their city faces. From there, collaborators can find ways to transition towards a circular economy and reduce CO2 emissions most effectively.

One way to work towards circularity is through technology like the 3DEXPERIENCE platform which brings all operations into a centralized environment. It provides a single source of truth for all stakeholders in the value chain and finds the right solutions for any given scenario. The platform also allows users to simulate cities virtually where designers can test out the most sustainable and cost-effective materials to use for new buildings and infrastructure, analyze data to help them understand how citizens are contributing to waste, find underutilized pockets of the city that can be transformed into green spaces and even utilize its built-in lifecycle assessment capabilities to monitor and measure the environmental impact of a product through its entire life cycle. 

Embracing digital tools and innovation

In order to build the city of tomorrow, it will require people to think outside the box. The challenges the world faces today are very different than they were thousands of years ago and new, innovative ideas will be required to revolutionize and protect the places we call home. Many city planners simply don’t have the right tools to bring their ideas from inception to life which is where technology can help. 

According to a recent report by ThoughtLab and co-sponsored by Dassault Systèmes, most future-ready cities are embracing digitalization as a way to anticipate and manage rising challenges. For example, virtual twins for cities can help city leaders understand the complexity of their territories by visualizing them in a 3D representation and experimenting with individual buildings, infrastructures and entire cities to create “what-if” scenarios to develop the best solutions for the future. 

Examples of sustainable cities


Rennes Métropole was looking for a way to address the complexity of their city and involve all regional stakeholders using an innovative tool. Instead of working in silos as a traditional city does, they utilized the 3DEXPERIENCE platform on the cloud to work systematically for better planning and managing purposes. They created a virtual twin where all stakeholders can simulate the city and analyze mobility, demographics and health data to make appropriate decisions for the future of the city. 

Hong Kong

The government of Hong Kong, China was looking to establish itself as a smart city and address urban challenges, quality of life, sustainability and operational efficiency. The city, jointly with ARUP engineering firm, chose the 3DEXPERIENCE platform as the foundation of the planning department and have used the centralized environment to solve challenges related to underground management, mobility, collaboration and approval. By visualizing Hong Kong in 3D, multiple departments are able to successfully leverage the large amounts of data available to them and use it to the benefit of its citizens.

Zenata Eco-City 

Zenata Eco-City is one of the first eco-cities in Africa and is an example of an urban area being designed from the ground up to be sustainable. With a complete public transportation system, paths for pedestrians and cyclists, over a thousand acres of green space and 3 activity centers, Zenata was designed with the well-being of its citizens first. Moving forward, city planners, architects, engineers and other decision-makers plan on using the 3DEXPERIENCE platform to support collaboration, urban infrastructure design and to ensure their decisions are well aligned with their objectives to make Zenata a beautiful, healthy place to live. 

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