China's central bank governor Yi Gang says corporate default risks are one challenge facing the economy. Yi addressed an online meeting of the Group of 30 International Banking Seminar over the weekend. He says China is doing well overall, but the default risks of certain firms and operational difficulties of smaller banks may be future problems. Yi says regulators are keeping a close eye, so those problems do not become systemic risks. The comments come amid growing concerns in recent weeks over developer China Evergrande Group's debt issues.