India is strengthening its nuclear deterrence by not only inducting new ships but also testing advanced missiles capable of hitting the entire Pakistan or China or any enemy country that dares to attack India. The undersea nuclear strike capabilities will multiply manifold as the Defence Research and Development Organisation (DRDO) is now readying to test the K-6 submarine-launched ballistic missile (SLBM), after successfully testing and validating the K-4 SLBM. Designed to strike targets at distances of up to 8,000 kilometres, the K-6 SLBM is expected to travel at hypersonic speeds of around Mach 7.5, significantly complicating interception by enemy missile defence systems, said reports.
The progress on K-6 comes amid major milestones achieved in India’s existing sea-based missile programme. Recently, the Indian Navy successfully conducted the third consecutive test of the K-4 ballistic missile from the nuclear-powered submarine INS Arihant. With a range of approximately 3,500 kilometres, the K-4 is capable of hitting targets deep inside adversary territory, including anywhere in Pakistan, even when launched from the Arabian Sea. The repeated successful trials indicate that the missile is now operationally ready for induction into the submarine fleet.
The K-4 missile represents a major leap in India’s indigenous missile development. Entirely designed and manufactured within the country, the missile is hypersonic, travelling at speeds exceeding Mach 5. It can carry a payload of up to 2,000 kilograms and is capable of delivering both conventional and nuclear warheads. Advanced materials used in its construction reduce radar detection, while satellite-based guidance enhances accuracy and target strike probability.
With the induction of the K-4, India has effectively completed its nuclear triad—possessing the capability to launch nuclear weapons from land, air, sea, and from submerged platforms. This capability significantly boosts India’s second-strike potential, a cornerstone of credible nuclear deterrence.
India’s submarine-launched missile arsenal already includes the K-15 (Sagarika), which has a range of over 750 kilometres, weighs around 6–7 tonnes, and can carry a nuclear warhead of up to 1,000 kilograms. The missile measures roughly 10 metres in length and can reach speeds close to Mach 7.5. The larger K-4, weighing up to 19 tonnes with a range exceeding 3,500 kilometres, allows Indian submarines to strike distant targets while remaining concealed underwater.
Once operational, the K-6 will give India the ability to target far-off regions while maintaining stealth patrols in deep waters, placing it among a select group of nations with advanced SLBM technology.
India’s accelerated naval weapons testing is widely seen as a strategic response to growing security challenges in the Indo-Pacific region. With the K-4 now combat-ready and the K-6 moving closer to trials, India’s underwater nuclear capabilities are entering a decisive new phase.
