PMSSY: the central scheme under which new AIIMS institutions are sanctioned

The Pradhan Mantri Swasthya Suraksha Yojana (PMSSY) began with an announcement in 2003 of six AIIMS-type hospitals. The scheme was approved in March 2006. Its primary objective is to correct regional imbalances in the availability of affordable and reliable tertiary level healthcare, and to improve medical education in under-served or backward States. Besides new AIIMS, PMSSY also covers upgradation of existing government medical colleges. As per the PIB release cited here (2017), 19 AIIMS and 71 medical colleges or institutions were being taken up. That release lists Kerala only under upgradation: Thiruvananthapuram, Kozhikode and Alappuzha medical colleges.

Announced: 2003 (six AIIMS-type hospitals) Scheme approved: March 2006 AIIMS undertaken (per 2017 PIB release): 19 Medical colleges for upgradation (per 2017 PIB release): 71
Why it matters for exams: PMSSY is a standard Union health-scheme question, and its objective of correcting regional imbalance is the examinable core.
Kerala PSCUPSC

In plain words

PMSSY Pradhan Mantri Swasthya Suraksha Yojana — A Union health scheme for AIIMS-type institutions and upgradation of government medical colleges.

AIIMS All India Institute of Medical Sciences — A tertiary-care medical institution set up under PMSSY in many States.