Fascinating info Arvind, i was in 2015 toying around with the idea of Farming Consulting . Leveraging the agricultural knowhow of our farmers for urban consumption requirements, using their insights and keen agri-sense to build urban farms in apartment complexes using the latest greenhouse tech. The produce can be freshly sourced to Reliance Fresh, BigBasket , Hotels and, at a scalable level, even involving digital tech to manage stock, inventory, forecasting etc.
Its a grandiose plan i just keep in mind but never acted on, but as i earlier mentioned , now for me its about preparing for a dystopian future.
I had no idea about the water problem i would face, let alone the rain water harvesting solution you are mooting (though in bangalore right now rain water harvesting has been mandatory for new constructions > 1000sqt or so since 2012.)
EDIT - Also what about drip irrigation that the Israelis pioneered ? you think that can be factored into the solution ?
I think since technical feasibility is not a problem, we can heave a sigh of relief, and i sense there's a startupidea here somewhere, so its just about networking with other agripreneurs like yourself, but i am not a subject matter expert , just a social entrepreneur with roots in rural Kerala
EDIT - Maybe the solution is mushrooms or some above ground edible fruits which can be sold to FMCG/retailers/vendors as part of MVP (Minimum Viable Plan / Product) , we can use that to show the market research.
We should network on this.