China operates a nationwide blacklist that contains the names and personal information of people who have been ordered by the courts to pay back money, also known as "laolai."

Some local phone operators have assigned special ringtones to warn people that they're calling laolai, and asks them to "please urge the person" to pay back the money.

This is part of China's wider campaign to police citizens' behavior. The country is rolling out a "social credit system," which aims to track, reward, and punish people for their behavior.

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Some phone companies in China are assigning special ringtones for people in debt, which warn callers that they are about to speak to someone who owes debt and asks them to get them to pay up.

China currently operates an extensive blacklist system, which names and shames people who have been ordered by the court system to repay their loans. They're called "laolai," which can be roughly translated to "deadbeat debtors."

The country, which traditionally emphasizes saving and considers borrowing money a taboo, has been coming up with unusual measures to shame laolai into repaying their debt.

In some localities, if you call someone who owes money, instead of a traditional ringing noise you get a special recorded voice note. It tells you that you're calling someone who owes money, and tells you to "please urge the person" to pay back their debts.

Some local telcom operators have assigned special ringtones to warn people that they're calling court-registered debtors, and tells them to get them to pay up. Reuters/Edgar Su

These ringtones have been in place since at least 2017. That year a court in Guanyun county, eastern China, worked with a local telcom operator to design a ringtone that tells callers.

According to the state-run Xinhua news agency: "The subscriber you are calling has been put on a blacklist by the Guanyun County Court for failing to repay their debts. Please urge the person to fulfill his legal obligations."

"The Guanyun County People's Court appreciates your support. Thank you!" the automated message ends by saying.

All phone numbers registered to the laolai's name are stuck with that feature, which only the court or telcom operator can cancel when the debtor has repaid all their loans, according to Pan Xingjun, a court employee who spoke to Xinhua.

The South China Morning Post reported in March that several regions are enforcing special ringtones like this.

Passengers on the platform of the Beijing Railway Station in February 2016. Millions of people on China's debtors' blacklist have been barred from booking train and plane tickets. REUTERS/Damir Sagolj

China has over the past few years created a variety of ways to name and shame debtors on the blacklist.

The country's supreme court operates a publicly accessible and searchable online database, which contains the full names and partially redacted government ID numbers of laolai around the country. Upon clicking on the person's name, you can also see their ages, home cities, and details of their debt.

The Chinese Supreme Court operates a publicly accessible and searchable online database containing the names and personal information of people who owe debt. Supreme People's Court of China

Many people on the blacklist are banned from booking train tickets, buying property, or holding high-ranking positions in state-owned companies, The Telegraph reported.

The province of Hebei, northern China, also developed an app to tell people whether they are walking near the court-registered address of a debtor, state media reported earlier this year.

More than 17 million people were barred from restricted from buying plane tickets, and some 5.5 million weren't allowed to purchase high-speed train tickets last year, the South China Morning Post reported in February, citing government statistics.

Read more: China reportedly monitors what civil servants do outside work as the country rolls out its ambitious social credit system

Chinese President Xi Jinping's government is trying to police the behavior of the country's 1.4 billion citizens. EnginKorkmaz/iStock, Etienne Oliveau/Getty Images, Samantha Lee/Business Insider

The blacklist is just one part of China's wider campaign to police the behavior of its 1.4 billion citizens.

The country is currently rolling out its ambitious "social credit system," which aims to track people's behavior, and reward or punish people depending on how they behave.

The system — which operates separately from the blacklist system — is piecemeal and still in trial mode in various municipalities, though authorities previously said they wanted to launch it nationwide in 2020.

Social credit systems across the country have so far cracked down on dog owners, jaywalkers, and people found misbehaving or loitering in public, among others.