Payment protection insurance (commonly abbreviated PPI) is a special insurance. People who get a loan can get an insurance against dying, having an accident or becoming unemployed during the period of this loan. If the person taking the loan dies, the rest of the loan is paid by the insurance company; if they become unable to work because of an accident, or because of unemployment, the insurance company will pay the installments.
This form of insurance has often been criticised because it is expensive; also the insurance and the people selling the insurance usually have high margins on these kinds of insurance.