India Receives Fourth S-400 Air Defence Missile System from Russia

Key Facts

• India's fourth S-400 missile system is scheduled to arrive by mid-May 2026.
• India signed a contract on October 5, 2018, with Russia for five S-400 squadrons worth approximately $5.43 billion.
• Three squadrons had been delivered and inducted by early 2023, the fourth is en route for deployment in Rajasthan, and the fifth is expected by November 2026 near the northern border with China.
• The Defence Acquisition Council approved a proposal in early 2026 for acquiring five additional S-400 squadrons, potentially doubling the inventory to ten systems.
• India also approved the purchase of 288 missiles (120 short-range and 168 long-range) worth about $1.1 to $1.2 billion, replenishing missile stocks expended during Operation Sindoor in May 2025.
• Operation Sindoor in May 2025 marked the first operational use of the S-400 system by India in a four-day conflict with Pakistan, where the system successfully engaged Pakistani fighter aircraft, drones, and radar installations, demonstrating its combat capability.

Background & Context

The S-400 Triumf is a Russian long-range surface-to-air missile system capable of engaging aircraft, cruise missiles, and ballistic missiles at various ranges up to 400 kilometers. India procured this advanced system under a 2018 deal to strengthen its layered air defence network amid evolving regional threats from Pakistan and China. Deliveries were phased over several years, with delays caused by geopolitical challenges such as the Russia-Ukraine conflict and Russian defence supply chain disruptions.

The fourth squadron is planned for deployment in Rajasthan to cover the western frontier, while the fifth is likely to be positioned along the northern border to enhance air defence capability against China. Following successful operational deployment during the 2025 conflict with Pakistan, India has moved to increase its missile inventory and expand the number of S-400 units by acquiring additional squadrons. The Defence Acquisition Council's approvals and contract processes ensure oversight and alignment with India's defence procurement policies.

Why This Matters for Exams / Exam Relevance

This development illustrates India's strategic defence procurement and modernisation efforts in the 2020s, especially pertaining to missile defence and geopolitical security concerns. Key dates such as the 2018 contract signing, delivery milestones (December 2021 for first squadron, July 2022 for second, early 2023 for third, mid-2026 and late 2026 for fourth and fifth respectively) help contextualize the timeline of capabilities enhancement. Understanding the geographical deployment (Rajasthan for western border, northern borders for China) is critical for defence and geography subjects. The operational use of the system in Operation Sindoor links defence technology with real-world conflict scenarios in India-Pakistan relations. Finally, the role of the Defence Acquisition Council highlights the policy and administrative framework behind India's defence procurement.