Bloomberg: Royal Dutch Shell Plc and AES Corp. said that a United Nations program to approve carbon credits to offset emissions by companies is slow and opaque. “There’s a clear lack of transparency in how the Clean Development Mechanism board makes its decisions,” Ming-Yee Lim, environmental products originator for Shell, said today at the Carbon Forum Asia 2010 conference in Singapore. “This has made us delay our approval process and impacts investor confidence to a large extent.” The CDM mechanism…