Sounds like way too little to make a difference in precip doposit rates. The US has been researching cloud seeding since...oh I don't know at latest 1950's. The idea is to disperse a particulate into a water vapor dense cloud to cause the condensation of water onto the silver particles. I'm no expert, but it seems like it's hit or miss science at best.
We can all relax. Now we know the real innocent purpose of all those missiles we thought were pointed at Taiwan. Maybe the liberals will use this as another excuse to back off from our implementing anti-ballistic-missile defense.
I think you are right - somthing is not on the up and up with this story. I don't see how cigarette-sized "chunks" would do more than fall, or even if they disintegrated, produce enough condensation nuclei to cause a small cloud to form, let alone generate rain over an area the size of Bejing or more.
My guess is that it simply finally rained and the state controlled media pounced at the opportunity to show the subjects just how advanced and mighty their technology was.
For another guess, I wouldn't be surprised if part of their drought problem was the presense of too much condensation nuclei in the area due to completely unchecked air pollution. Too much of condensation nuclei inhibits the formation raindrops by keeping them way too small (can't get big enough to for a real rain drop basically).
But hey, they are a devleoping nation and shouldn't be looked down upon for not requiring the advanced pollution controls and strict pollution regulations like we do. Hell, even the perfect, got to do something now before the world ends global change people think it's okay to give China a pass...
"I'm no expert, but it seems like it's hit or miss science at best."
Call it global condensation. Wonder how we can stop it?