From Xinhua, via China Daily:
Each year, more than six million farmers leave villages in the locality for cities for jobs in transportation, construction or cleaning, Chongqing itself absorbs 400,000 new migrant farmer workers annually.
A sample survey by the Chongqing Municipal Agricultural Bureau shows that 92 percent of migrant farmer workers say they feel biased by urbanites, which not only hurts their feelings but also may easily trigger social conflict.
Reports said a string of violence has occurred recently in some Chinese cities due to discrimination against the migrant farmer workers.