In 2018, the then-chairman of the Armament Research Board, DRDO, asserted that India is capable of creating an ICBM that can reach targets more than 10,000 kilometres away and that in addition to developing the ground-based Agni-6 missile, the DRDO is also experimenting with an underground version of the missile ie. Underground Agni-6.
The first Agni-6 ICBM could be produced by DRDO over the next three years thanks to the start of development work in this area. It is unclear whether India will test this ICBM in 2025 or 2026, but this information suggests that Agni-6 development has moved from the design and technical maturity phase to the actual developmental phase.
According to a large number of Indian defence specialists, Agni-6 will be a land-based version of the K-6 submarine-launched ballistic missiles, which have been approved for development for some time.
India’s Agni-5 which has a range of 5000–8000 km was first tested about ten years ago and then publicly shown, Since then, DRDO’s attention has been focused on developing the K-4, K-5, and K-6 SLBMs from the K Family series which are essential parts of India’s second strike nuclear capabilities.