China has given unconditional clearance to a proposed merger between Royal Dutch Shell (RDSa.L) and BG Group (BG.L), clearing the final key regulatory hurdle for the $70-billion tie-up, Shell said on Monday. The clearance means the pre-conditional approval process is complete, the Anglo-Dutch company said in a statement. Prior to the approval, industry sources told Reuters that Chinese authorities were pressing Shell to sweeten long-term gas supply contracts as the world’s top energy consumer faces a large surplus of the supplies as a demand boom at home falters.