"An invisible cage": How China is policing the future

The latest generation of technology digs through the vast amounts of data collected on their daily activities to find patterns and aberrations, promising to predict crimes or protests before they happen. They target potential troublemakers in the eyes of the Chinese government — not only those with a criminal past but also vulnerable groups, including ethnic minorities, migrant workers and those with a history of mental illness.

They can warn the police if a victim of a fraud tries to travel to Beijing to petition the government for payment or a drug user makes too many calls to the same number. They can signal officers each time a person with a history of mental illness gets near a school.

It takes extensive evasive maneuvers to avoid the digital tripwires. In the past, Zhang Yuqiao, a 74-year-old man who has been petitioning the government for most of his adult life, could simply stay off the main highways to dodge the authorities and make his way to Beijing to fight for compensation over the torture of his parents during the Cultural Revolution. Now, he turns off his phones, pays in cash and buys multiple train tickets to false destinations.