NEW DELHI: Former chairman of the Telecom Regulatory Authority of India (TRAI) Rahul Khullar passed away early today morning following a prolonged illness.

Khullar, a 1975-batch Indian Administrative Service (IAS) officer, served as a secretary of the ministry of commerce and trade, and was later appointed as the telecom regulator in May 2012. replacing JS Sarma.

Succeeded by a 1978 batch Jharkhand cadre IAS officer Ram Sewak Sharma in July 2015, Khullar navigated a three-year long tenure at a time when the telecom sector was plagued with uncertainty in the aftermath of the 2G spectrum scam.

He was a post graduate in Economics from the Delhi School of Economics. He taught briefly at Delhi University's Hansraj College, before joining the IAS in 1975.

NITI Aayog vice-chairman Rajiv Kumar took to Twitter to condole Khullar's death.

"Just heard very sad news of Rahul Khullar's passing away. Known him since 1969 when we were together in St Stephen's, then in MoF & again in ADB. One of the sharpest minds with impeccable integrity. Deepest condolences to Sindhushree. May his noble soul rest in eternal peace (sic)," he tweeted.

Economist and former civil servant NK Singh expressed his shock and grief at Khullar's passing and remembered him as a "man of amazing rectitude."