More Than Just a Green Roof

'Agritecture' is an idea to make cities more self-sustaining (https://www.theguardian.com/cities/gallery/2019/feb/09/can-agritecture-make-cities-self-sufficient-in-pictures). It basically is an idea involving processes like hydroponics where food plants are grown within some of the buildings. There is scope for doing this and it would certainly reduce some of the food transportation costs (as well as, in some cases, using 'waste' heat). Of course, some of the required minerals, along with water and light would have to be transported to the sites. Its real benefits might well depend on what energy is used to provide the illumination that is needed for photosynthesis. Some of the contaminated city air might also be problematic.