Singapore Telecommunications-owned Australian telecom firm Optus has paid a A$1.5 million (S$1.3 million) fine after the local communications watchdog found large-scale breaches of public safety rules around emergency services, the Australian Communications and Media Authority (ACMA) said on Wednesday (March 6). An investigation by the ACMA has revealed that about 200,000 Optus mobile customers were left at risk due to…