Principal advisor in PMO PK Sinha resigns on personal grounds New Delhi: March 16: Former Cabinet Secretary and Principal Advisor in the Prime MinisterтАЩs Office (PMO), P.K. Sinha, has resigned from his post on personal grounds. Sources said the retired 1978-batch IAS officer of the Uttar Pradesh cadre put in his papers on Monday evening. Sinha was appointed in the PMO in September 2019 following the general elections, after he retired as the Cabinet Secretary. After Principal Secretary Nripendra Misra, Sinha became the second high-profile official to the exit the PMO. Misra had resigned in August 2019 after the Lok Sabha elections, prompting a rejig in the PMO. (IANS)