All the states (except Andhra Pradesh and Jammu & Kashmir, who opted out of it) contribute the above mentioned percentage of seats to the central government pool. Apart from these, central institutions like AIIMS, PGIMER (Chandigarh) and JIPMER (Puducherry) conduct their own entrance examinations. The private colleges too conduct entrance tests, either individually or as consortia.
The counselling (the seat allocation process based on personal appearance) for various exams for entrance to post graduate medical courses takes place from February to May. People who succeed in multiple exams attend all these counsellings in search of the best available option. As a result, often, seats of All India pool remain vacant even after the second counselling, as some students get better options through state entrances — or in some other institutes. For the last few years, the wait-listed candidates have been approaching the Supreme Court and a third counselling (termed - extended second counselling) has thus become the norm . This leads to a delay in beginning the session every year.
During the hearing of one such case, the Supreme Court suggested the authorities to consider a common entrance test (CET) for medical colleges. The Medical Council of India (MCI) then prepared a draft for such an exam which would be the common gateway to all the government and private medical colleges of the country. The proposal received a thumbs up from the ministry and on 29th June 2010 it was announced that this CET would come into effect from this session itself.