The contemporary global arms race is marked by high-speed weapons, particularly among the US, Russia, and China. In South Asia, India too is on a trajectory to acquire hypersonic capabilities, representing a significant shift in the regional strategic environment. However, South Asia is a nuclearized region that remains predominantly vulnerable to crises and instability due to persistent territorial disputes. With advanced characteristics, including hypersonic speeds (Mach 5 and beyond) and high maneuverability, India’s acquisition of hypersonic weapons will increase pre-emptive temptations and counterforce posturing. This article examines the impact of hypersonic weapons on escalation dynamics and strategic stability in South Asia.

Hypersonic weapons are generally categorized into two major types: hypersonic cruise missiles (HCMs) and hypersonic boost glide vehicles (HBGVs). The HCMs travel the whole flight at the speed of Mach 5 or beyond, using a rocket booster for initial acceleration and scramjet engines for a sustained hypersonic speed throughout the flight. They remain within the altitudes of 20 to 80 km, below the Karman Line, which is the official edge of space. In contrast, the BGVs have multiple phases. In their boost phase, the rocket booster accelerates the glide vehicle to achieve hypersonic speed. Once the missile is about to enter space, the glide vehicle detaches from the booster and follows a short ballistic trajectory. On re-entering the earth’s atmosphere, the vehicle glides through the air, covering a major portion of the flight path until it dives down towards the target in the terminal phase.

In South Asia, India’s ambitions for hypersonic weapons date back to 2008, when the Defense Research and Development Organisation (DRDO) announced plans to develop a Hypersonic Technology Demonstrator Vehicle (HSTDV). According to the DRDO, the first successful test of an HSTDV was conducted in September 2020. It originally aimed to develop and test a scramjet engine to further India’s hypersonic technology. During the test, the vehicle travelled for 22 to 23 seconds at the speed of Mach 6.

Another test of the HSTDV was conducted in January 2023, where the initial take-off proved successful; however, the scram-jet failed to deliver the vehicle. Subsequently, in November 2024, the DRDO conducted a flight trial of India’s first long-range hypersonic missile, capable of terminal manoeuvres and the ability to carry various payloads for ranges greater than 1500 km. The long-range and, particularly, ‘terminal manoeuvrability’ of this missile suggests that it is most likely an HBGV. The same missile is alternatively called Long-Range Anti-Ship Missile (LR-AShM), which was revealed during the 77th Republic Day parade in January 2026. Additionally, its multi-domain nature suggests that it is intended for use by the Navy, Air Force, and Army in multiple configurations.

While previously, ambiguity prevailed regarding India’s scramjet success, in April 2025, the DRDO ran a ground test of the scramjet combustor for over 1000 seconds. Following this test, India’s defence ministry claimed that “this test serves as a ground for full-scale flight-worthy combustor testing, adding that “it forms a base for the nation’s hypersonic cruise missile development programme”. Following the sequence, in July 2025, the DRDO tested a dual-capable Extended Trajectory Long Duration Hypersonic Cruise Missile (ET-LDHCM), with a 1500 km range and Mach 8 speed. The scramjet engine used in this missile is presumably the one tested in April 2025, designed for long-duration hypersonic flight. Adding to that, India is aiming to develop BrahMos-II, an advanced version of BrahMos, which will utilise the earlier indigenously developed scram-jet combustor tested in April 2025.

Nevertheless, the HCMs travel most of their flight path at low altitudes, i.e., 20-40 km, making them stealthy against ground-based radars. Particularly in mountainous terrain, HCMs take refuge under the blind spot of a ground-based radar, thus escaping detection. Besides, there are some trade-offs – the high air density at low altitudes might cause the scramjet engine to overheat and fail mid-flight. Therefore, India might remain with medium-range HCMs or develop many versions of HBGVs that travel at comparably higher altitudes.

Furthermore, India’s increased investment and sharp leap in hypersonic technologies indicate that these capabilities will soon be operational, causing a destabilising role in South Asia for several reasons. First, the undetectable and ‘hard-to-intercept’ nature of hypersonic missiles increases pre-emptive temptations. Their high penetration rate against air/missile defense systems offers confidence of early success in a crisis scenario. Pakistan currently possesses multiple air defense systems, including HQ-9/P, LY-80, HQ-16A, and FM-90, as part of a Comprehensive Layered Integrated Air Defence. However, their effectiveness against hypersonic missiles remains in question. Therefore, in any potential crisis with Pakistan, India is more likely to use these weapons early in a conflict – skipping multiple rungs of escalation, which is destabilising for crisis stability.

Secondly, the high speed, precision, and accuracy of hypersonic missiles make them a feasible option for counterforce targeting. These characteristics perfectly align with India’s ambitions of a so-called limited war doctrine. By enabling rapid strikes against high-value military assets, including missile launchers, airbases, and command-and-control centers, hypersonic systems enhance the reliability of swift counterforce operations under the nuclear overhang. Concurrently, these capabilities may reinforce New Delhi’s belief that escalation could be controlled. However, since Pakistan adheres to the Quid-Pro-Quo+ strategy, a harder retaliatory blow from the Pakistani military would prompt New Delhi to rethink that escalation could be tightly managed.

Thirdly, given their dual-capability, it remains a big challenge to identify whether the incoming hypersonic missile is nuclear or conventionally armed. India’s newly tested hypersonic missile, the ET-LDHCM, is designed to carry both conventional and nuclear warheads. This blurring of the line between conventional and nuclear warheads makes it difficult to precisely assess the intent of such a speedy missile in real time. In any crisis, if such missiles are launched by India, Pakistan might perceive or interpret them as a nuclear strike even if they are conventionally armed. Additionally, the dual nature and speed of hypersonic missiles compress decision-making time, and therefore, Pakistan may find itself in a “use it or lose it” dilemma. Under such pressures, the probability of uncontrolled and rapid escalation remains high.

Furthermore, India primarily relies on the Russian-made S-400 ballistic missile defense systems (BMDs) to counter aerial threats from China and Pakistan. The acquisition of BMDs may also provide a false sense of security against retaliatory strikes, as no defense system has a 100% success rate. Besides, the S-400 system's interception profile remained low during the May 2025 India-Pakistan conflict, particularly because of the proximity between the two sides. Nevertheless, given India’s quest for a limited war with Pakistan, it is more likely that the former will employ hypersonic missiles in a potential engagement to gain an early advantage. Hence, India’s hypersonic capabilities, together with a false sense of security due to BMDs, will highly impact the strategic environment.

In conclusion, India’s pursuit of hypersonic technologies carries significant implications for deterrence, arms control, and escalation dynamics in the region, particularly with respect to Pakistan, which already has a tense relationship with India. Moreover, India’s acquisition of hypersonic weapons demonstrates the pursuit of counterforce options, leaving Pakistan at a certain disadvantage. To prevent New Delhi from exploiting the asymmetry, Islamabad also intends to develop hypersonic technologies to balance the equation. This action-reaction cycle further impacts the arms race, which is one of the crucial elements of strategic stability. In essence, hypersonic missiles do not strengthen stability but instead shrink the space for caution in the India-Pakistan strategic equation. Given the severity associated with hypersonic missiles, both sides should engage in dialogue, discourage counterforce strikes, and develop crisis communication mechanisms to avoid any misadventure.

Muhtasim Afridi is an intern at the Strategic Vision Institute, Islamabad. He can be reached at: muhtasimafridi166@gmail.com