Trading was halted on Sri Lanka's stock exchange seconds after it opened Monday when the blue chip index dropped 5.92 percent following a mass cabinet resignation in the face of an economic crisis..The S&P index fell more than the five percent needed to trigger a circuit breaker that halts trading for half an hour, the Colombo Stock Exchange said..(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)