哪来的20%严重污染？这个是2012做的不是20年前
http://online.wsj.com/news/articles/SB10001424052702304626304579507040557046288
Nearly 3% of arable land in China was found to be either moderately or seriously polluted, the report said, without defining what those levels of contamination mean. Pollution was particularly severe in eastern China's Yangtze River Delta, the Pearl River Delta in the south and old industrial zones in the northeast, it said.
Pollution of farmland is of particular concern in China because of how little of it has. According to the most recent national land survey, China had 334 million acres of arable land at the end of 2012, roughly 37 million acres above the government's "red line" for the amount of farmland necessary to feed the country's population.
