The S-400 Triumf (NATO reporting name SA-21 Growler) is a long-range, mobile surface-to-air missile system developed by Russia’s Almaz-Antey. In Indian service the system has been christened “Sudarshan Chakra” and forms the outermost, longest-range layer of India’s multi-tiered integrated air defence network, capable of engaging aircraft, cruise missiles, and ballistic missiles at ranges of up to 400 km.[1]
India signed a contract with Russia in October 2018 for five S-400 squadrons at a cost of approximately $5.43 billion, despite the risk of US sanctions under the Countering America’s Adversaries Through Sanctions Act (CAATSA). India was ultimately granted a sanctions waiver in view of its long-standing defence relationship with Russia and the strategic necessity of the system amid growing two-front air-power challenges from Pakistan and China.
The S-400 is a networked, multi-missile system rather than a single weapon: each squadron/regiment typically comprises multiple mobile launcher vehicles, a 91N6E “Big Bird” long-range acquisition radar, 92N6E “Grave Stone” engagement radars, command posts, and support vehicles, allowing simultaneous engagement of numerous aerial threats across different altitude bands. The system fires a family of interceptor missiles, including the very-long-range 40N6 (up to 400 km), the 48N6 series (~250 km), and the shorter-range 9M96E and 9M96E2 missiles for closer, more manoeuvrable targets.
Deliveries began in December 2021, with the first two squadrons deployed to cover the Punjab sector against Pakistan and the northeastern and eastern Ladakh sectors against China. By 2026, three of the five contracted squadrons had been delivered and inducted, covering the Punjab, Rajasthan, and northeastern/Ladakh sectors. The fourth squadron arrived and became operational by the end of May 2026, and the fifth and final squadron under the original 2018 contract was expected to arrive by November 2026, completing the initial five-squadron deployment years later than originally envisaged due to supply-chain disruptions linked to the Russia-Ukraine war.[2]
The S-400/Sudarshan Chakra network was operationally active during Operation Sindoor in May 2025, engaging Pakistani drones, cruise missiles, and aircraft attempting cross-border strikes. The system was credited with a record-range engagement, downing a high-value Pakistani surveillance aircraft at a reported distance of more than 300 km, demonstrating the practical reach of the 40N6 missile in live combat conditions.[3]
India’s deployment strategy allocates roughly 65 percent of S-400 assets to the western front facing Pakistan and 35 percent to the northern and eastern sectors facing China, reflecting the relative intensity of the respective threat environments. In late March 2026, India’s Defence Acquisition Council approved a further procurement package worth approximately ₹2.38 lakh crore (roughly $28-30 billion), which includes five additional S-400 squadrons. If concluded, this would double India’s total S-400 inventory from five to ten squadrons, transforming the system from a frontier deterrent into a nationwide, strategic-depth air defence backbone.[4]
The S-400 operates as the outermost layer of a broader layered air-defence architecture that includes India’s indigenous Akash medium-range SAM, the Barak-8/MRSAM, and shorter-range point-defence systems, all cued by an integrated air command and control network. This layered approach allows India to hand off threats between systems of increasing precision and decreasing range as they approach protected assets.
The S-400 gives India one of the most capable ground-based air-defence umbrellas in Asia, closing a long-standing capability gap against high-altitude, long-range aerial threats including advanced fighters, airborne early warning aircraft, and cruise missiles. Its demonstrated combat performance during Operation Sindoor has reinforced its role as a central pillar of Indian air defence and a key rationale for the planned doubling of the fleet.
| Type | Long-range mobile surface-to-air missile system |
| Manufacturer | Almaz-Antey (Russia) |
| Indian Designation | Sudarshan Chakra |
| Missile Range | Up to 400 km (40N6); ~250 km (48N6 series); shorter-range 9M96E/9M96E2 |
| Engagement Altitude | Up to ~30 km |
| Contract | October 2018, ~$5.43 billion for 5 squadrons |
| First Delivery | December 2021 |
| Deployment Split | ~65% Pakistan front, ~35% China front |
| Planned Expansion | 5 additional squadrons approved March 2026 (total 10) |