PARIS/ZURICH (Reuters) – Holcim (HOLN.VX) called a halt on Monday to its merger with Lafarge (LAFP.PA), pressing the French company to renegotiate the deal terms and putting their plan to create the world’s biggest cement maker at risk. “The Holcim board of directors has concluded that the combination agreement can no longer be pursued in its present form,” Holcim said in a statement, saying it was ready to talk about both the share exchange ratio and “governance issues”.