Governments mostly try to implement smart city concepts in existing cities
Nowadays about 3.7 billion people live in cities, and by national definitions of “urban” the figure is closer to 4.8 billion. The UN expects two-thirds of global population growth up to 2050 to take place in cities, and the number of megacities to rise from 33 to 37. Therefore, the “smart city” question became a topical issue over the past few years.
So what is smart cities development really about? The definition agreed by the ITU and UNECE describes a smart sustainable city as an innovative city that uses information and communication technologies and other means to improve quality of life, the efficiency of urban services and competitiveness, while meeting the needs of present and future generations. In other words, for smart sustainable cities technology is the means, and quality of life and sustainability are the goal.
The main aim of smart city development projects is to create an environment in which every megapolis resident enjoys a comfortable life while working and rest conditions are decent.
To build a smart city from scratch
There are a lot of new and interesting concepts of “built from scratch” smart cities. It is expected that such cities would be based on a water recycling system, e-mobility, and eco-driving infrastructures, etc. Masdar City (UAE), Chengdu Great City (China), and Tianjin Eco-city are the best-known examples of the “built from scratch” smart city concept. The world’s first city beneath the surface of the ocean, Ocean Spiral (Japan), has so far remained a concept proposed by the construction company Shimizu.
However, such projects require enormous costs and they are quite difficult to implement. Masdar City’s completion date has been pushed back to 2030 and its original zero-carbon goal scaled back, while Tianjin Eco-city was home to just over 120,000 permanent residents in 2022, against a plan for 350,000 by 2020.
Thus, governments mostly try to implement smart city concepts in existing cities.
Smart cities India: a mission closed, not finished
India is a large-scale example of this approach. Its Smart Cities Mission, launched in June 2015, selected 100 existing cities and was officially closed on 31 March 2025. By March 2025, 93% of the more than 8,000 planned projects had been completed, but only 18 of the 100 cities had finished all of theirs, and Indian cities still sit outside the global top 20 of the IMD index.
The criteria for selecting smart cities
- The effective application of energy resources;
- The development of alternative sources of energy;
- The use of environmentally-friendly modes of transport;
- Urban transport infrastructure and car parking system optimization;
- The introduction of innovative technologies. The development of the Internet of Things;
- The spread of computers and smartphones and uninterrupted access to Wi-Fi.
Smart cities world rankings
Every smart cities list depends on who is counting and how. Across the smart cities world, rankings differ depending on the methodology. The IMD Smart City Index 2026, which is based on residents’ perceptions, is led by Zurich, Oslo and Geneva. The ISUI/PolyU index, which relies on public data, puts Stockholm, Washington D.C. and Barcelona on top.
Five leading smart cities
Singapore
This city has long been among the leaders in “best smart city” ratings. It ranked 9th in the IMD index in 2025 (down from 5th a year earlier) and 21st in the ISUI/PolyU index. The key feature of this city is a reorganized traffic flow system. Traffic lights, along with road signs and security cameras are able “to talk” to each other. Moreover, they can “talk” to cars on the road and straight back to a centralized government agency.
There are multiple automated car parks. The fully automated car parking system knows the number of vacant parking spots and can send this data to a special mobile app. A city resident is able to download this app and use it. That’s how people always know where they can find a parking space.
Furthermore, the government has developed a special 2D map, where people can track traffic flow. The government has also reserved the right to amend or update the map information. Now they can mark the congested districts, change bus routes, etc.
The government has also developed Virtual Singapore, a 3D model launched in 2014 and completed in 2022, regarded as the first digital twin of an entire country. It helps to implement some essential solutions virtually. For example, it is possible to carry out the testing of an emergency evacuation.
New York
This city regularly appears in “smart city” charts and ratings, though its position varies widely: 7th in the ISUI/PolyU index, but only 49th in the IMD index. The critical feature of this city is undoubtedly the security system. New York streets are full of surveillance cameras, and more than 2,000 acoustic sensors across the five boroughs are designed to identify the sound of a gunshot and instantly send a signal to the police. The NYPD has used the ShotSpotter system since 2015 and renewed the contract in 2025 for three years. However, a 2024 audit by the city comptroller found that only 13% of its alerts were confirmed shootings.
The city is also known for its BigBelly system. It is a system of smart garbage bins, which are endowed with chips that detect when the bin is full, allowing trash collectors to know that it is time to make a pick-up.
New York has much more if we are talking about the smart city concept. Smart Lighting (a retrofit of the city’s 250,000 street lights to LED, projected by the city to save about $14 million a year in energy and maintenance), Smart Water Metering, and Air Quality Monitoring (to address the issue of air pollution) programs have already been launched and show favorable results overall. The systems are still not perfect, but they work. After all, they are the systems that make New York a role model.
London (Smart Cities UK)
London is the flagship among smart cities in the UK, and the only UK city in the top 10 of either index (6th in the IMD index and 4th in the ISUI/PolyU index in 2025). London, similar to Singapore, launched a smart car parking system in 2014. Besides, London firefighters use SAS to explore risk and drive prevention strategies aimed at reducing fires, death, and injury. London underground stations are equipped with temperature and humidity sensors.
Foster + Partners proposed the SkyCycle project in 2014. It was about new cycle routes throughout the city. Basically, the idea was to construct new cycle routes above the railroad lines. It would reduce traffic congestion and provide security for cyclists. However, the network was never built: it remained at the proposal stage, and the then-mayor dismissed it as too expensive.
Barcelona
The capital city of Catalonia is also considered to be one of the most advanced smart cities, ranking 3rd in the ISUI/PolyU index in 2025. This city is known for its smart car parking system, smart garbage bins, and smart public transport stops.
Barcelona-El Prat Airport is now part of the EU’s biometric Entry/Exit System, which has operated there since October 2025 and became fully operational across the EU on 10 April 2026. It replaces passport stamping for non-EU travellers with fingerprint and facial registration, but its rollout has caused longer queues at several European airports.
Barcelona has also launched a smart lighting system, which has produced about 30% energy savings and, by the city’s own figures, saves around $37 million a year.
The capital city of Catalonia suffers from drought during the summer. An automated irrigation system helps address this issue and saves water (the city reports a 25% saving).
Moreover, Barcelona streets are equipped with air pollution and traffic control sensors. It is all possible due to the Sentilo platform, which developed these solutions, especially for the Barcelona infrastructure, and was released as open source so other cities can reuse it.
Copenhagen
The capital city of Denmark is famous for its cycling infrastructure and ranked in the top 10 of both indexes in 2025 (7th in IMD, 9th in ISUI/PolyU). The government implemented a project on equipping bike sensors in 2017. These sensors tell cyclists data for road congestion and the air pollution index.
The government actively supports “smart” ideas and “smart city concept” solutions. It developed the City Data Exchange solution jointly with Hitachi, a marketplace for sharing public and private data. The pilot ended in 2018 because of low demand, and the city says it is applying the lessons learned to its own data policy.
In addition, Copenhagen is a city with a well-developed cashless payments system. Cash was used for just 9% of payments in physical shops in Denmark in 2025, down from 23% in 2017. After card-payment outages in July 2025 and May 2026, though, the central bank urged Danes to keep a little cash on hand and launched an offline card contingency.
