In London, in a former bomb shelter underneath Clapham Common, for example, Growing Underground cultivates leafy greens, such as watercress, rocket and coriander. Built to shelter up to 8,000 people during the second world war, its tunnels now house rows of plants.“It was all [done using] standard agricultural equipment, save for LEDs,” says Steve Dring, co-founder of Growing Underground. LEDs provide the right level of light and heat in an energy efficient manner.

Source: Data analysis, tech and fish waste make urban farms viable