Those loans are coming dueforrepayment in the next few years, and the local governments and their construction partners are in no condition to repay them.
As their countries' bond yields rise, it becomes more expensive for governments to sell more debt, which leads to a vicious circle as the old debt comes dueforrepayment.
Since some of this debt is dueforrepayment next year, the Bank of England has a deadline for deciding whether to roll it over into a perpetual zero-interest debt - which would be seen as, in effect, writing off the debt.