The Supreme Court of India is the highest judicial forum and final court of appeal under the Constitution of India, the highest constitutional court, with the power of constitutional review. Consisting of the Chief Justice of India and 30 sanctioned other judges, it has extensive powers in the form of original, appellate and advisory jurisdictions.

A citizen of India not exceeding 65 years age per Article 124 of the constitution who has been

• a judge of one high court or more (continuously), for at least five years, or
• an advocate there, for at least ten years, or
• a distinguished jurist, in the opinion of the president,
is eligible to be recommended for appointment, a judge of the supreme court.

A Person who has retired as a Judge of the Supreme Court is debarred from practicing in any court of law or before any other authority in India.

As per the Constitution, as held by the court in the Three Judges Cases – (1982, 1993, 1998), a judge is appointed to the Supreme Court by the President of India on the recommendation of the collegium — a closed group of the Chief Justice of India, the four most senior judges of the court and the senior-most judge hailing from the high court of a prospective appointee.

[Previously] Judges used to be appointed by the President on the advice of the Union Cabinet.

President can remove a judge on proved misbehaviour or incapacity when Parliament approves with a majority of the total membership of each house in favour of impeachment and not less than two thirds of the members of each house present.

The collegium system has come under a fair amount of criticism. In 2015, the Parliament passed a law to replace the collegium with a National Judicial Appointments Commission (NJAC). This was struck down as unconstitutional by the Supreme Court, in the Fourth Judges' Case, as the new system would undermine the independence of the judiciary.

- extracted from Supreme Court of India, Wikipedia as on 27th February 2018