BANGKOK — India’s power sector has been targeted by hackers in a long-term operation thought to have been carried out by a state-sponsored Chinese group, a U.S.-based private cybersecurity company detailed in a new report. Over the last several months, the Insikt Group, the threat research division of Massachusetts-based Recorded Future, said it has collected evidence that hackers targeted seven Indian state centers responsible for carrying out electrical dispatch and grid control near a border area disputed by the two nuclear neighbors.