OECD: Organisation of Economic Co-operation and Development
OGL: Open General Licence
OIC: Organisation of Islamic Countries
OIGS: On India Government Service
OIL: Oil India Limited
OM: Order of Merit
ONGC: Oil and Natural Gas Commission
OPEC: Organisation of Petroleum Exporting Countries
OSCE: Organisation for Security and Cooperation in Europe
OSD: Officer on Special Duty
OXML: Open Extended Marking Language
P
PAC: Political Affairs Committee; Public Accounts Committee
PACER: Programme for Acceleration of Commercial Energy Research
PAN: Permanent Account Number (of Income-Tax)
PATA: Pacific-Asia Travel Association
PCS: Public Civil Service; Punjab Civil Service
PIB: Press Information Bureau
Pin Code: Postal Index Number Code
PIO: Persons of Indian Origin
PLF: Plant Load Factor
PM: Post Meridiem; after-noon; also Postmaster; Prime Minister; post-mortem (after death)
PMG: Postmaster General
PN: Participatory Note
PO: Post Office; Postal Order
POPs: Persistent Organic Pollutants; Point of Purchase
POTA: Prevention of Terrorism Act
POW: Prisoner of War
PP: Public Prosecutor; Particular Person
PRO: Public Relations Officer
PS: Post Scriptum; Post Script; written after
PSC: Public Service Commission
PSE: Public Sector Enterprises
PSLV: Polar Satellite Launch Vehicle
PTA: Preferential Trade Area
PTI: Press Trust of India
PTO: Please Turn Over; Privilege Ticket Order
PUFA: Poly Unsaturated Fatty Acids
PVC: Param Vir Chakra
PVSM: Param Vishisht Sewa Medal
PWD: Public Works Department