India extended a mandate to power plants to import coal until March as the driest August in more than a century pushed electricity demand to a record, putting a strain on supplies of the nation’s main generation fuel.​Plants designed to run on domestic coal have been asked to import 4% of their supplies of the fuel through March to avoid outages, extending an earlier direction to buy from overseas until the end of this month, power secretary Pankaj Agarwal said in an interview.