A guide to green cities and where to find them

07 January 2022 | Celia Topping

Imagine a leafy, pollution-free city centre with cyclists pedalling along wide, safe bike lanes and solar panels on every roof. There’s no waste on the street and the only cars on the road are electric, emitting a quiet hum, rather than a noisy roar. Take a deep breath – the air is pure and clean, and you’re surrounded by trees, shrubs and plants trailing from buildings and window ledges. 

This may be what you think about when you hear the term, “green city”.  But does the definitive “green city'' actually exist? It’s difficult to pinpoint the “greenest city”, because there are so many factors that could contribute to what being “green”, or “sustainable” means. 

But when research is done and lists are compiled, there are always a few cities that crop up time after time when comparing green credentials. Want to know which ones they are? Then join us on an eco-friendly armchair journey to find out…

5 key attributes of a green, sustainable city

So what are the characteristics of a sustainable or green city? And where in the world can we find them? Rapid growth tends not to make a good bedfellow for sustainability – and a concrete jungle filled with polluted air and waste spilling over the streets certainly wouldn’t win any prizes. But is it merely a question of tree-count that wins the race? Whatever it is, cities need to become more sustainable if we have any chance of reaching our net zero targets and responsibly address the climate crisis.  

Finding the world’s greenest cities depends on a number of factors. The most sustainable cities tend to score highly on most of the following categories:

1. Renewable, clean energy

More than half of the world's population lives in cities. And from those cities comes around three quarters of the world’s carbon emissions from final energy use. The pressure is on to reduce those emissions to help stop climate change

Worldwide access to reliable sustainable energy is one of the UN’s Sustainable Development goals. So it’s a fine place to start for any city with green ambitions – especially in the energy and transport sectors where a lot of carbon emissions are released. Using renewables such as geothermal, hydro, solar, and wind energy means the city can reduce its carbon footprint as a whole.

Reykjavik runs entirely on geothermal and hydropower sources1, as well as hydrogen buses on the streets. In fact, the whole of Iceland is fossil fuel free2

2. Good public transport

Transport emissions are one of the biggest hurdles to achieving a net zero future. A massive 27% of the UK’s emissions come from transport, with 91% of that coming from road transport3. So it’s vital for cities to focus sustainability efforts on greenifying transportation. Ensuring residents have access to cost-effective public transport takes cars off the road and reduces harmful emissions. 

Some of the public transport systems that green cities have introduced are:

  • Trams
  • Metro systems
  • Underground railways
  • Buses
  • High speed technology concepts like Hyperloop

Other ways of promoting alternative travel include:

  • Low-emission zones, which discourage carbon-heavy cars from entering the city centre. 
  • Reserving certain lanes for buses, electric cars, and carpooling
  • Making sure there are wide, safe bike lanes throughout the city
  • Setting up excellent electric car infrastructure and prioritised parking

London and Singapore offer high-quality bus and underground rail systems to transport city dwellers around the city. And low-emission zones have been created where cars with higher emissions must pay a charge.  

3. Green buildings

40% of the world’s greenhouse gas emissions come from buildings4. Green buildings, which are designed in a way to be more energy efficient and pollute less, can reduce these emissions by up to 32%5. Research has found that improving our indoor environment has a positive impact on both our physical and mental health6

So what makes a green building? The most widely recognised certification for green buildings is LEED (Leadership in Energy and Environmental Design). These are the kind of criteria considered in order to construct a green building.

  • Smart heating and cooling systems
  • Water conservation
  • Natural, eco-friendly building materials to reduce VOC (volatile organic compounds) emissions.
  • Highly efficient lighting systems including motion sensors
  • Improved ventilation and insulation
  • Solar panel energy generation
  • Lots of natural light
  • Rooftop planting

The green architecture movement in Paris has helped make the French capital one of the top cities for green buildings7. Sounds like a good excuse to go get some fresh croissants…

Find out how you can help green up your workplace in our handy blog on going back to work the eco-friendly way

4. Public green spaces

Wide open green spaces and woodland within the urban environment score high on the list of criteria for green cities. Being outside in nature is good for our physical and mental wellbeing – so easy access to places where we can relax and breathe deeply is essential. 

Even in cities where space is limited, there’s still room for some green infrastructure, such as:

  • Parks, greenways, and trails
  • Street trees
  • Protected conservation areas
  • Community gardens
  • Community allotments and affordable garden spaces

Offering city dwellers green space can also help control pollution and encourage biodiversity.  

Around half the city of Vienna is green, with parks, city farms, gardens, and allotments all over the city That means there’s approximately 120 square metres of green space for every resident8

5. Recycling and waste management programmes

Recycling has now become the norm in the UK and in most countries across the globe, so waste isn’t ending up in landfill and causing environmental damage. Urban centres have seen huge benefits from introducing recycling programmes and further moves towards circular economy should see yet more.

Delhi has achieved a lot over the past few years with regards to reducing waste. Thousands of “eco-clubs” have been created in schools across the city9. These help children to understand the importance of protecting their environment and how they can take action. The city also has a culture of “careful consumption” and implements waste reduction policies10

Read our informative article on recycling: why it’s important and how to do it on Planet OVO. 

What is the greenest city in the UK?

bristol suspension bridge hot air balloons

One city that consistently tops the list of the UK’s greenest cities is Bristol. In fact, it was the first UK city to attain the revered accolade of European Green capital for its environmental efforts. This cultured West Country city is a leader in smart heat technology – and Bristol’s aiming to become the first zero-carbon smart city by 203011. Go, Bristol!

Surveys have also found that Bristolians recycle or compost 47% of their household waste, and use less than 3000kWh of gas a year12. Pretty impressive. One of the UK’s first green bookshops was opened in Bristol in the 1980s, and the city is, of course, the birthplace of green energy supplier, OVO Energy! Add to this great air quality, more and more cyclists, plus plenty of open green spaces and city farms, and it’s no wonder Bristol tops the eco charts. 

What is the greenest city in Europe?

The beautiful Danish city of Copenhagen is often found at the top of the list of European green cities. Having set a goal in 2012 to become the world’s first carbon-neutral city by 2025, the capital is right on target. 

Ambitious goals like that one, plus fervent action, set Copenhagen above the rest of Europe by some margin. Investment into eco-style living is high here, with a focus on quality of life at the forefront. Only 29% of households own a car13, and bikes are by far the preferred method of transport, with cycle lanes winding their way all around the city. It’s said the Danish capital has actually overtaken Amsterdam in being the most bike-friendly city in the world. 

But it’s not only bikes that set Copenhagen apart. Hydrogen-powered taxis are common and the city is in the process of switching its buses from diesel to electric. There are open public spaces aplenty and free natural swimming pools are available in the harbour. WIth regards to waste management, residents and politicians are united – the city aims for an impressive 70% recycling rate14.  You can even recycle at vending machines and get money back.

Organic eating has become central to the Danish diet, and two thirds of the hotels are eco-certified15. This means sustainable energy, food, and design are key considerations. And sustainable fashion is high on the list of the cool Danish kids. It’s hard not to find an area in which Copenhagen isn’t sustainable! 

Which is the greenest city in the world?


This is a really tricky one, as there are many cities that score highly for all the above criteria and more. But apart from the cities already mentioned, the one that tops a number of sustainable city lists is Canada’s coastal city of Vancouver. 

Vancouver has water, mountains, and forests galore, so it’s unsurprising its eco-credentials are pretty darn high. But it’s not just nature where Vancouver excels. The city launched the Greenest City initiative in 2008 and has been striving to cut its carbon emissions ever since. Here’s a few of the things that make Vancouver green:

  • The city has the lowest per head greenhouse gas emissions of any North American city16. This is probably because of the carbon tax introduced in 2008, which taxed heating and petrol. 
  • 125,000 trees have been planted since 2010.
  • 50% of journeys happening in the city are made by foot, bike, or public transport, which cuts road emissions massively. 
  • Single-use plastics have been banned since 2019.
  • The leading 5 star hotels use their roofs for veggie growing and bee hives17.
  • Vancouver is considered the home of climate activist group Greenpeace.
  • The city is striving to be zero waste by 204018.
  • There are more than 300 LEED-certified buildings
  • 93% of the city’s electricity comes from renewable sources19

Even with all these innovations and initiatives, Vancouver still acknowledges that its carbon footprint is 3 times bigger than the earth can sustain at the current time.

So although green cities are on the rise, there’s still a long way to go to zero carbon.

5 ways to make your city greener

No matter where we live, we can all do our bit to make our city that little bit greener, even from the comfort of our own home

  1. Home energy makes up 26% of our personal carbon footprint20. So a simple way to reduce your emissions is to switch to a renewable energy supplier. Like OVO for example! We offer 100% renewable electricity as standard21, and plant a tree every year in your name too22
  2. Ditch the car and get on your bike! Transport makes up around 27% of the UK’s carbon emissions23. And many of those short journeys could easily be made on foot or by bike. It’s not only good for the environment, but good for you too. Read our beginner’s tips to cycling in the city.
  3. Recycling is key to protecting our environment. Would you believe that Britain generated 221 million tonnes of total waste in 2016? Without recycling, all that rubbish ends up in landfill which does terrible harm to our planet. 

Head over to our article on recycling, and why it’s important to find out more. 

  1. Resist your fast fashion tendencies. Our desire to look good has an enormous impact on the environment – the fashion industry consumes more energy than the aviation and shipping industry combined24. But the rag trade is one of the industries that is increasingly getting to grips with the circular economy. So it’s easier than ever to shop sustainably if you choose the right brands. 

Read more about how fashion impacts the environment and how you can shop smarter in our practical blog. 

  1. Go electric! Technology is improving, prices are dropping and range is increasing. There’s never been a better time to switch your gas guzzler for a clean, green, carbon-kicking machine! More electric cars on the streets means cleaner air for everyone, and a drastic reduction in carbon emissions. Plus, they’re cheaper to run than their petrol counterparts. There’s a vast range of electric cars to choose from, so whether you prefer to buy or lease, the future definitely is electric. 

Keep up with the innovative electric car trends in our fascinating blog. 

Switch to green energy 

If you want to do good for yourself, your city, and the environment as a whole, switching to renewable energy is one of the best choices you can make. At OVO, we’re working towards being a net zero-carbon business by 2030.  And as part of our ambitions, we’re helping our members become more sustainable too. 

We only offer 100% renewable electricity25, and we plant a carbon-munching tree26 for every new OVO customer. And you’ll also get:

  • Free access to OVO Greenlight: a unique tool that gives you personalised tips on how to cut your carbon footprint
  • The chance to upgrade to OVO Beyond27, for 100% carbon-neutral energy and extra tree-planting power

Sources and references:




















20 Based on analysis carried out by the Carbon Trust for OVO Group (2020), 26% of an average individual’s carbon footprint in the UK comes from energy. In this analysis, the carbon footprint includes the following lifestyle categories: energy, transport, shopping, food and drink and holidays. This carbon footprint data has been calculated using BEIS 2020 emission factors. This excludes emissions from things that the average person cannot directly control such as supporting the NHS, defence, government bodies, etc. Please note these figures are not reflective of potential changes to your habits during the coronavirus pandemic

21100% of the renewable electricity we sell is backed by renewable certificates (Renewable Energy Guarantee of Origin certificates (REGOs)). See here for details on Renewable Energy Guarantee of Origin certificates and how these work. A proportion of the electricity we sell is also purchased directly from renewable generators in the UK.

22 Each year, OVO plants 1 tree for every member in partnership with the Woodland Trust. Trees absorb carbon dioxide from the atmosphere, so tree-planting helps to slow down climate change.



25 100% of the renewable electricity we sell is backed by renewable certificates (Renewable Energy Guarantee of Origin certificates (REGOs)). See here for details on Renewable Energy Guarantee of Origin certificates and how these work. A proportion of the electricity we sell is also purchased directly from renewable generators in the UK.

26 Each year, OVO plants 1 tree for every member in partnership with the Woodland Trust. Trees absorb carbon dioxide from the atmosphere, so tree-planting helps to slow down climate change.

27Enjoy even greener energy with OVO Beyond in comparison with our standard OVO plans. In addition to 100% renewable electricity as available with our standard plans, OVO Beyond reduces your yearly carbon emissions from the energy used in your home that is supplied by OVO to net zero by providing 100% carbon-neutral gas (15% green gas and 85% offset) and offsetting all associated lifecycle carbon emissions involved in the production and consumption of your electricity & gas, you will also get 5 trees per year in UK schools and communities and other green benefits. The renewable electricity we sell is backed by renewable certificates (Renewable Energy Guarantee of Origin certificates (REGOs)). See here for details on Renewable Energy Guarantee of Origin certificates and how these work. The green gas we sell is backed via renewable certificates (Renewable Gas Guarantees of Origin (RGGOs)). See here for details on Renewable Gas Guarantees of Origin and how these work. We offset the remaining emissions by supporting UN REDD+ carbon reduction projects that are certified to the Verified Carbon Standard or the Gold Standard. See here for more information on how we restore nature and protect rainforests with our offsetting programmes.