Short answers, pulled from the story.
The KARST proposal stands for Kilometer-square Area Radio Synthesis Telescope. It was an ambitious Chinese bid to host the international Square Kilometre Array during the 1990s by leveraging natural limestone depressions in southwestern provinces.
KARST would have consisted of about thirty individual elements working together as a single system. Each element measured approximately two hundred meters in diameter designed to fit snugly into natural limestone depressions.
A site survey of 288 suitable locations was performed in Pingtang County, Guizhou Province. Officials searched for unpopulated areas with guaranteed very low levels of human-made radio interference to ensure detection of faint signals from deep space.
Four sites were initially proposed including South Africa, Australia, Argentina and China but Argentina and China were dropped from consideration after considerable site evaluation surveys. On the 25th of May 2012 it was announced that the SKA will be split over the South African and Australian regions instead of becoming an Asian one.