- Helsinki is the capital and largest city of Finland. It is located on the southern coast of the country and is known for its beautiful scenery, rich history, and vibrant culture.

- The city has a strong commitment to sustainable development and has been recognized for its efforts in this area. In 2019, Helsinki was ranked the most sustainable city in the world by the Arcadis Sustainable Cities Index.

- Some of the key factors that contribute to Helsinki's sustainability include its efficient public transportation system, its commitment to renewable energy, and its green spaces.

- Helsinki is also a leader in the circular economy, which is an economic model that aims to minimize waste and maximize resource efficiency.

Espoo:

- Espoo is the second largest city in Finland. It is located on the western coast of the country and is part of the Helsinki metropolitan area.

- Espoo is also committed to sustainable development and has been recognized for its efforts in this area. In 2019, Espoo was ranked the second most sustainable city in the world by the Arcadis Sustainable Cities Index.

- Some of the key factors that contribute to Espoo's sustainability include its innovative urban planning, its focus on energy efficiency, and its commitment to green infrastructure.

- Espoo is also a leader in the use of smart technology to improve its sustainability.

Tampere:

- Tampere is the third largest city in Finland. It is located in the western part of the country and is known for its industrial heritage and its vibrant arts and culture scene.

- Tampere is also committed to sustainable development and has been recognized for its efforts in this area. In 2019, Tampere was ranked the third most sustainable city in the world by the Arcadis Sustainable Cities Index.

- Some of the key factors that contribute to Tampere's sustainability include its strong public transportation system, its commitment to renewable energy, and its emphasis on sustainable urban development.

- Tampere is also a leader in the use of collaborative governance to address sustainability challenges.

Oulu:

- Oulu is the fourth largest city in Finland. It is located in the northern part of the country and is known for its high-tech industry and its research institutions.

- Oulu is also committed to sustainable development and has been recognized for its efforts in this area. In 2019, Oulu was ranked the fourth most sustainable city in the world by the Arcadis Sustainable Cities Index.

- Some of the key factors that contribute to Oulu's sustainability include its strong commitment to renewable energy, its focus on sustainable urban development, and its emphasis on innovation.

- Oulu is also a leader in the use of green technology to improve its sustainability.

Overall, Finnish cities are leaders in sustainable urban development. They are committed to reducing their environmental impact, improving the quality of life for their residents, and creating a more sustainable future for all.