NEW DELHI: In a boost for India’s missile defence capabilities, the long-awaited fourth squadron of the “S-400 Triumf (now called ‘Sudarshan’) air defence systems has started arriving in India from Russia” through the ship route.“The first batch of the fourth squadron of S-400 has arrived. Once the complete systems reach here, it will be deployed,” a source told TOI.The Russian-made S-400 played a key role in thwarting the Pakistan-launched missiles during last year’s conflict in May and had then also secured the longest-recorded surface-to-air kill of 314 km by bringing down a high-value Pakistan surveillance aircraft.The S-400 air defence system is part of the $5 billion contract in Oct 2018 under which India was to acquire five S-400 squadrons from Russia, three of which arrived two years ago and the remaining two were delayed due to the ongoing Ukraine war. As the fourth S-400 squadron has started arriving in batches now, the fifth squadron is expected to reach India by Nov.India deploys the earlier three squadrons in strategic sectors like in the Punjab-Jammu region, Rajasthan-Gujarat region and Sikkim sector to form a triangular protective shield along its western and northern borders. The fourth system is also likely to be deployed in the western sector, keeping in mind the threat perception from Pakistan after last year’s conflict.A standard squadron consists of 8 to 12 mobile Transporter Erector Launchers (TELs). Each TEL carries 4 missile tubes, resulting in 48 ready-to-fire missiles on the launchers at any given time. With reloading and support vehicles present, a single squadron can collectively field up to 128 missiles. Each S-400 unit features long-range detection up to 600 km and can engage multiple aerial threats, including fighter jets, cruise missiles and ballistic missiles, at varying altitudes and distances.Impressed with S400 performance during last year’s conflict, the Defence Acquisition Council (DAC) has already cleared the acquisition of five more squadrons of the Russian systems.India is also working on an indigenous programme, codenamed Project Kusha, to develop its own air defence systems capable of shooting down enemy drones, missiles and hostile aircraft at different ranges.