Thats exactly why you keep multiple ports and keep the schedule and deployment patterns secret. Plus, you keep multiple subs. So anytime there is a bunch of subs deep in the water hidden from enemy eyes.
That is, assuming you have enough SSBNs. You need about 5 to have 1 permanently in its area of operation (same as with US carriers groups).
" INS Arihant, was launched on 26 July 2009 in Visakhapatnam (India) and is currently undergoing sea trials. The Navy plans to have six nuclear-powered ballistic missile submarines in service in the near future. She is both the first boat of the
Arihant-class nuclear-powered ballistic missile submarines and the first nuclear-powered submarine to be built in India."
https://en.wikipedia.org/wiki/Indian_Navy#Submarines
Arihant would be INs first and - for the time being only - SSBN
" Exact number of planned submarines remains unclear, according to media reports about three to six submarines are planned to be built
.The first boat of the class, INS
Arihant is expected to be commissioned by 2016. The first four vessels are expected to be commissioned by 2023. In December 2014, the work on a second nuclear reactor began and the second boat, INS
Aridhaman is being prepared for sea trials. The next three ships in the class, after the lead ship, will be larger and have 8 missile launch tubes to carry up to 8 K4 and a more powerful pressurized water reactor than INS Arihant. A larger follow on class to the Arihant class is also planned, these new boats will be capable of carrying 12 to 16 ballistic missiles"
https://en.wikipedia.org/wiki/Arihant-class_submarine
1 by end of 2016, 4 by end of 2023 (if all goes to plan). That mean 1 at sea at all times. Not a whole bunch.
K-15
Sagarika submarine launched ballistic missile
- 750 km (435 mi) with 1,000 kg payload
- 1,900 km (1,200 mi) with 180 kg payload
https://en.wikipedia.org/wiki/Sagarika_(missile)
Depending on the weight of a nuclear warhead, it may well be that IN SSBN need to remain relatively close to e.g. Pakistan if they are to strike effectively ... Note that the wiki says ' nuclear capable' , not ' fitted with a nuke' : it is fully operational in that sense?
" The navy is coming up with a secret base on the east coast, under the code name Project Varsha, to berth its upcoming fleet of nuclear submarines."
http://www.dnaindia.com/india/report-navy-creating-a-new-base-for-nuke-submarines-1395220
You can't and don't park your SSBNs in just any port.... IN will have a special base for its nukes.