Based on your query, I would recommend using Scratch to create a sustainable city. This platform allows students to learn coding through the creation of interactive stories, games, and animations.

In the context of your query, students can use Scratch to create an interactive game or animation that simulates a sustainable city. They can incorporate elements such as renewable energy sources, waste management systems, and sustainable transportation methods. This would not only help them understand the concept of sustainability but also allow them to apply their coding skills in a real-world context.

Key features of Scratch that would be particularly useful for this project include:

• Creativity and engagement: Students can use their creativity to design and build their sustainable city, making the learning process more engaging and enjoyable.
• Collaboration: Students can work together on their projects, promoting teamwork and collaboration.
• Curriculum integration: This project could be integrated into various subject areas, such as science (for understanding sustainability concepts), geography (for planning the city layout), and math (for calculating energy usage, waste production, etc.).

Remember, Scratch is a free platform, so there are no costs associated with using it for this project.