In 1957, the government of India requested Lord Mountbatten, then the First Sea Lord, to provide India a target submarine which could be the oldest and cheapest available to serve as a foundation to build a submarine force for the Indian Navy (IN), a request he flatly refused to consider.
In 1959 the Indian Navy asked the UK for three operational submarines, this never happened as the UK refused the soft credit terms sought by India. The Indian Navy finally got a Break when the Soviet Union came to India’s rescue and provided the Indian Navy with eight Foxtrot class submarines between 1967 & 1974.
Submarine acquisition in India was hit by a double whammy in the 1980s with the German HDW Submarine scam in 1987 which saw the much required class of six HDW type 209 submarines being acquired being reduced to four boats. To make matters worse, India also had to prematurely return the Charlie class SSN it had leased from the USSR for 10 years after the dissolution of the Soviet Union, it had only served the IN for a bare three years. The Russians came to the rescue once again and the fleet was bolstered by 10 877EKM (KILO) class boats which were inducted between 1986 & 2000.
In the year 2000 the Indian Navy adopted a 30 year submarine building plan which would see the induction of 24 new submarines by 2030 with 18 SSKs(Submersible ship killer) & 6 SSNs(Submersible ship nuclear) joining the fleet by 2030.
This was later tweaked to 24 SSKs with all 6 SSNs getting their own separate category & $14Bn approval under the strategic nuclear submarine program in February 2015.The plan called for half the Slated strength of 24 SSKs or 12 boats to be built on two simultaneous lines with foreign collaboration by 2012 with another 12 to be built completely of an indigenous design between 2012-30, needless to say that plan lies in tatters.