In response to ghalibkabir’s comments about the K-4, of January 23, 2020 my comments are:
For several reasons the K-4 submarine launched ballistic missile (SLBM) may not be fully deployed, economical or strategically effective until 2030. Since 2010 the K-4 has undergone several pontoon launches, one reported (but unproven) "dummy payload" submerged launch from INS Arihant on March 31, 2016 but then a failed pontoon launch on December 17, 2017 launch. Two successful pontoon launches took place on January 19 and 24, 2020. But the K-4 may need 3 years for 10 successful tests involving submarine launch and actual missile flight.
All launch tubes in INS Arihant and INS Arighat may take 3 years to convert/develop for the K-4. So maybe 2026 for full K-4 deployment on Arihant and Arighat.to be considered reliable.
India has been unable to develop multiple warheads/MIRVs per missile and may take 10 years to do so. Only one warhead per K-4 with only 4 K-4s from Arihant would not be a economical/viable deterrent. A K-4 needs 3 or 4 warheads/MIRVs to be an adequate weapon system on economic and strategic grounds. As Arihant and Arighat can only take 4 x K-4s Chinese anti-ballistic missile (ABM) systems might be able to shoot all of them down. It is unknown whether K-4s can deploy "penetration aids" such as chaff or decoys to compensate for the current one warhead per K-4 problem. So India may take 10 years (until 2030) to finally develop reliable MIRVs.
Ghalibkabir refers to is the K-4's warhead maybe having an explosive power of 50 kT. This is perhaps insufficient to destroy deep dug Chinese command centers. 50 kT suggests India has only developed boosted fission nuclear weapons (as at the 1998 Shakti I test). India may not have developed more advanced 2-stage thermonuclear weapons (when on SLBMs often rated at 100-150 kT). 50 kT is less than SLBMs of other nuclear powers. For example Missile Threat indicates a Chinese JL-2 can deploy one warhead of 1 MT or 3 to 8 MIRVs with 20/90/150 kT warheads. Also China’s Type 094 “Jin class” SSBNs deploy 12 JL-2s.
So the K-4 may take until 2030 to be a fully deployed, economical and strategically effective SLBM.