China has banned almost 7 million people from taking flights and high-speed trains over the past four years as a penalty for not repaying their debts, the country’s Supreme Court has announced. The penalty system is part of efforts to build a nationwide “social credit” system that will rate every Chinese citizen by collecting big data on financial, legal or social misdeeds. The debtors’ travel ban has been touted as an important first step for building the structural links needed to implement such a comprehensive monitoring program. Since 2013 the Supreme Court has operated a “discredited” blacklist of long-term debtors who have been ordered to repay what they owe, and banned from flights and high-speed rail, according to the Financial Times. Part of the reason for the social credit system is the lack of personal bankruptcy law and a comprehensive financial credit system.