This is interesting. Here is the Popular Science Article.
"Cloud seeding, involving the injection of silver iodide particles into the atmosphere, helped clear some of the pollution from Beijing before the 2008 Olympics. But it does not always go so well. This time, cloud seeding is necessary to make actual rain, authorities said."
“Because clouds are boundless, weather control is boundless."
Anyway, it was a great class and a great semester!