The city was inspired somewhat by the ephemeral Neo Tokyo of Japanese dystopias but with less of a romantic air. The city would have the feel of being 21st century and yet old with loads of urban fungal growth around it as people adapted and changed the technology to make it more useful to the community (think of this scene from Lord Of War)
The alleyway to his house is stacked full of processed debris and as the door opens, three generations of his family are separating plastics and leather on the ground floor. On the top rests a solar panel and biogas barrels. The water runs hot through my hands from the solar heater, proving that these aren't notional concepts, they work and make a difference to people's lives.
A lot of these images happened to be from Mumbai anyway. The alien nature of the place, which looks imposing and closed, as if each building is it's own community adds to the feeling. If it was based on slums that were terraced houses in East London, the suspension of disbelief required to make the mental leap to giant mushrooms might not be possible.