India is expected to receive the India Fourth S-400 System by the end of the week of 19 May 2026. The advanced air defence system is part of a $5.43 billion defence agreement signed with Russia in 2018 for five S-400 squadrons. The system is operated by the Indian Air Force to strengthen India’s air defence capability.

What is the India Fourth S-400 System?

The S-400 Triumf is a Russian-made long-range surface-to-air missile system. It is designed to detect and destroy enemy aircraft, cruise missiles, and ballistic missiles at different ranges and altitudes.

The India Fourth S-400 System can track multiple targets at the same time and provide strong protection against aerial threats. It is considered one of the most advanced air defence systems in the world.

India-Russia Defence Deal

India signed the S-400 contract with Russia in 2018. The agreement included five S-400 squadrons for the Indian military. The original delivery schedule was planned to finish by 2023.

However, delays happened because of the Russia-Ukraine conflict and supply chain disruptions in the Russian defence sector. The fourth squadron was inspected by Indian Air Force officials in Russia in April 2026 before being transported to India by sea and air routes.

Deployment Along Western Border

The India Fourth S-400 System is likely to be deployed in Rajasthan. The deployment will strengthen long-range air defence coverage along India’s western frontier.

The fifth and final squadron under the original contract is expected to arrive by November 2026. Reports suggest it may be deployed near India’s northern border facing China.

India Plans More S-400 Systems

In March 2026, the Defence Acquisition Council approved a proposal to buy five additional S-400 systems. This decision could increase India’s total S-400 inventory to ten squadrons in the coming years.

India has also approved the purchase of 288 anti-aircraft missiles for the system. The package includes 120 short-range missiles and 168 long-range missiles with an estimated cost of $1.2 billion.

Role in India’s Air Defence

The India Fourth S-400 System plays an important role in protecting Indian airspace from enemy threats. The missile system has reportedly been used during Operation Sindoor in May 2025 by the Indian Air Force.

With more S-400 units being added, India is aiming to improve its defence preparedness and strengthen border security against modern aerial threats.