Male and female patients listen to a police officer as they go through a re-education class at the Kunming Municipal Compulsory Rehabilitation Centre in Kunming, Yunnan province November 12, 2009. The Kunming Municipal Compulsory Rehabilitation Centre, who said they are the biggest drug rehabilitation centre in Asia, marks 20 years of its establishment this year with over 3200 patients currently registered. Patients undergo treatments incorporating a strict regime of physical exercises, re-education classes and medication.[Agencies]