NEW DELHI: Reliance Jio has approache d the telecom tribunal seeking to be impleaded in a case filed by rivals Bharti Airtel and Idea Cellular against a recent predatory pricing order by the sector regulator, said lawyers aware of the matter.Telecom Disputes Settlement and Appellate Tribunal (TDSAT) has issued notices to Airtel and Idea to file their responses to Jio’s impleading application and the matter will heard in its next hearing on April 17, a lawyer representing one of the incumbent carriers said.The two incumbents had moved the tribunal arguing that predatory pricing rules issued by Telecom Regulatory Authority of India (Trai) on February 16 favoured new entrant Jio at their cost.“Reliance Jio and telecom watchdog had filed separate applications to be impleaded as parties in the appeals,” said the lawyer who requested not to be named. “Telecom watchdog’s petition was disposed of since Trai was already representing consumer interest in any case,” the person said.Reliance Jio did not comment on the development. The sector regulator had last month issued a tariff order that mandated a new formula to determine predatory pricing.