There are 4 (not 3) Arihants in construction (1 completed, 2nd one fitting out, and 3rd
and 4th ones undergoing hull fabrication by L&T) And there are 3 (with option for 3 more)
Avinash-class SSBNs in early stages of works right now. Total 7 SSBNs.
Its likely that after the 3 (or 6) Avinash-class subs are ready, IN may consider converting
all Arihants to SSGNs carrying 1,200-km ranged sub-launched version of Nirbhay or
LRCM cruise missiles.
The leasing of a 2nd Akula-II SSN (with option for buying at end of lease term, just like
the first one) is being seriously considered by IN top brass.