India takes delivery of its fourth S-400: the air-defense shield nears full strength

India has received the fourth of the five S-400 “Triumf” long-range air-defense systems it bought from Russia. Arriving amid Pakistan-China tensions, the delivery brings New Delhi close to full operational capability; the fifth and final system is expected in November 2026.

The S-400 Triumf, with a reach of up to 400 km, is among the world's longest-range air-defense systems. — The S-400 Triumf, with a reach of up to 400 km, is among the world’s longest-range air-defense systems.

At a Glance

What: India receives its 4th S-400 regiment
Supplier: Russia (2018 deal, $5.4 billion)
Total: 4 of 5 delivered; 5th in November 2026
One regiment: 16 vehicles (launchers, radars, C2)
Context: Pakistan-China tensions; regional air-power balance

The air-defense shield nears full strength

The fourth regiment of the Russian-made S-400 Triumf — known in Indian Air Force service as “Sudarshan” — has reached India. The $5.4 billion deal, signed at the Modi-Putin summit on 5 October 2018, covered five S-400 systems. The first arrived in December 2021 and the second in July 2022; with the fourth arriving in May 2026, New Delhi is approaching full operational capability. The fifth and final system is expected in November 2026.

Each regiment comprises 16 vehicles, including launchers, radars, command-and-control units and support vehicles. The delivery came amid rising tensions along the Pakistan-China axis and directly affects the regional air-power balance.

Each S-400 regiment is made up of 16 vehicles, including launchers, radars and command-and-control.

The S-400 and long-range air defense

The S-400 Triumf is a layered system able to use four missile types across different ranges and to track and engage many targets simultaneously. Its longest-range missile can reach targets at 400 km, and it is employed against a broad threat spectrum from aircraft to ballistic and cruise missiles.

Item	Value
System	S-400 Triumf (Indian name: Sudarshan)
Deal	2018, $5.4 billion — 5 systems
Delivery status	4/5 delivered; 5th in Nov 2026
One regiment	16 vehicles
Max range	~400 km
First delivery	December 2021

ASELSAN/ROKETSAN's SİPER is Turkey's indigenous long-range air-defense system. — ASELSAN/ROKETSAN’s SİPER is Turkey’s indigenous long-range air-defense system.

The S-400 has long made the procurement equation between NATO members and Russia contentious; Turkey’s own S-400 purchase generated a similar geopolitical debate. Against this backdrop, Turkey is building its layered air-defense architecture with national means — developing the indigenous SİPER long-range system, the HİSAR family and the ÇELİK KUBBE integrated concept to reduce foreign dependency.