yeh i think this could definitely work but i think there would definitely need to be strong focus on the sustainability aspects of it. maybe instead of maths because those design aspects of the city could fall under the art realm, we do two civics and community or whatever it is and focus on the damage to the environment, and that could definitely lead onto an english piece of writing where the students choose the perspective of an animal and how the environment has damaged their habitat. i suppose then the sustainability learning could look at the impact on animals which links into this piece of writing? not sure, just chucking it out there...