Chief Justice of India (CJI) Ranjan Gogoi administered the oath of office and secrecy to justices Krishna Murari, S Ravindra Bhat, V Ramasubramanian and Hrishikesh Roy in a simple function in courtroom 1.
The appointment takes the number of judges in the apex court to the total sanctioned strength of 34, including the CJI.
Justices Murari and Bhat headed the Punjab and Haryana and Rajasthan high courts respectively.
Justices Ramasubramanian and Roy headed the Himachal Pradesh and Kerala high courts respectively.
With a huge backlog of cases in the top court, the Centre had last Wednesday cleared the names of the four high court chief justices who were recommended by the apex court Collegium on August 30 for elevation.
The sanctioned strength of Supreme Court judges was increased days after the Chief Justice wrote to Prime Minister Narendra Modi to increase the number of judges in the top court.
According to a written reply by the Law Ministry to a Rajya Sabha question on July 11 this year, 59,331 cases are pending in the top court.
Due to paucity of judges, the required number of Constitution benches to decide important cases involving questions of law were not being formed, the CJI had said.
The Supreme Court (Number of Judges) Act, 1956 originally provided for a maximum of ten judges (excluding the CJI).
This number was increased to 13 by the Supreme Court (Number of Judges) Amendment Act, 1960, and to 17 in 1977.
The working strength of the Supreme Court was, however, restricted to 15 judges by the Cabinet (excluding the CJI) till the end of 1979. But the restriction was withdrawn at the request of the chief justice of India.
In 1986, the strength of the top court was increased to 25, excluding the CJI. Subsequently, the Supreme Court (Number of Judges) Amendment Act, 2009 further augmented the strength of the court from 25 to 30.