When Jia Xinru needed to borrow money to buy new clothes, order food and buy a projector to screen Breaking Bad on her wall, she had instant access to China's growing number of lenders via her mobile phone. The 24-year-old secretary is among millions of Chinese who have turned to proliferating online companies that dish out quick loans -- and are worrying the country's leadership. On Friday authorities issued new rules on microlending, designed to protect consumers and limit risk for creditors. The move was the latest aimed at tackling financial risks as the world's number-two economy faces ballooning debt that has drawn warnings of a potential global financial crisis. While most economists and analysts have focused their concerns on corporate debt, household debt has risen rapidly, roughly doubling since 2012, according to the Bank for International Settlements, known as the central banks' central bank. And smartphones have made it even easier for consumers to borrow cash in China, with e-commerce apps and mobile payment increasingly prevalent. Jia started accumulating her debt when she was in college, turning to tech titan Alibaba when she could not get a credit card. The ease of a few taps on her phone and a four minute wait led Jia to borrow and borrow and when she was finally able to take out a card, she used it to repay Alibaba's affiliate Ant Financial. But her debt reached roughly $9,000 this summer, and her monthly interest payments eclipsed her meagre salary. She described the debts as "snowballing", finding it harder to pay one debt as she borrowed to pay another. - 'Lending nirvana' - Alternative lending, with loans that can be wired to accounts within minutes, has taken off in China and accounts for 85 percent of the global market, according to a University of Cambridge report. By 2020, some estimates forecast the business could approach that of credit cards, suggesting some Chinese may be leapfrogging from plastic to mobile loans. Online lenders say most of their business comes from consumers and small businesses with little access to the formal banking system -- only a third of Chinese have credit cards, according to the central bank. "Most of our borrowers are in third or fourth tier cities," said a marketing employee at lending platform Guangxindai, who declined to give her name. "They have a hard time getting credit cards from banks." The business's growth comes as a new generation of Chinese shed their parents penchant for saving and embrace the credit culture. "There's a shift in China where people are now far more willing to take on debt," said Jason Bedford, executive director of Asian Financials Research at UBS Investment Bank. "There's been a tremendous push into consumer lending. It's seen as the next lending nirvana." The lending market exploded as regulators permitted the spread of platforms and products, with tech giants Alibaba, Tencent and Baidu all offering loans on demand through mobile apps. The space also attracted a number of upstarts. Online platforms Qudian, PPDAI Group and China Rapid Finance have listed publicly in the US this year and a number of similar firms are waiting on the sidelines. PPDAI's platform has attracted nine million borrowers, and the volume of issued loans has increased five-fold since 2015. - 'Start over' - But with an eye on predatory lending and its after-effects, the latest rules prohibit lending to consumers without income and cap interest rates at 36 percent annually. Regulators will also stop the approval of new online micro lenders. The move sent the stock prices of Qudian, PPDAI Group and China Rapid Finance tumbling in the past week. And Anne Stevenson-Yang, research director at J Capital Research, said the regulations could lead half of all online lenders to fold. Managing risk can be a tricky balancing act for online lending platforms when a large portion of the Chinese population lacks credit scores. Some platforms write off the bad loans while others have taken defaulted borrowers to court. Alibaba's affiliate Ant Financial has built a credit scoring system called Sesame Credit that tracks users on its platforms and provides perks to those with high credit scores. It also recently limited annualised interest rates to 24 percent. This autumn Jia turned to friends and family to pay off some of her credit card and Alibaba debt, with no interest. "When I pay it all off," she said, "I'm going to move to a new city and start over."