This is speculation.
Could rain be initiated by letting plants communicate with the air network through light or Li-Fi? This was my initial guess.
I mean. Any network optimized for life. Would not like to rain if the output was polluted. Nor would it like to rain on pavement.
Therefor there should exist plants optimized for cleaning polluted water.
The idea is then to create the machine learning model that predicts rain from a detailed map of plants, flowers, trees and pavement. Then grow different plants and remove pavement and see if the air network picks up on the change. More rain in the right places.
All this would be in vain if any pollution from cars ?still exist. So electric cars are a must and you get a quick fix by removing pavement.