New Delhi: Despite the threat of sanctions and diplomatic pressure by the United States (US), India went ahead with the S-400 Triumph missile defence system deal with Russia in October last year. India badly needed such a system to strengthen its air defence mechanism, given the hostile surroundings in which, it is located.

The delivery contract worth Rs 40,000 crore was signed during Russian President Vladimir Putin's visit India last year. It was then reported that the systems could be delivered to India by 2023.

The reports that are surfacing now state that Russia is likely to deliver the S-400 air defence missile systems to India within 18-19 months. This development would be welcomed by New Delhi as India was virtually defenceless against the incoming aerial attacks.

Soon after the deal was signed last year, Air Force Chief B S Dhanoa had termed it as a game changer. Defence and strategic matters expert Major General P K Sehgal had earlier told OneIndia that India's air defence capabilities badly needed an upgrade. He had said S-400 deal was the need of the hour given the growing threats from China and Pakistan.

The latest reports on early delivery quote Russian Deputy Prime Minister Yuri Borisov. "The advance payment has been received and everything will be delivered in strict accordance with the schedule, within about 18-19 months," Borisov had reportedly told state-owned broadcaster Rossiya-1.

Russia and India settled the issue of India's advance payment for the delivery of S-400 long-range surface-to-air missile systems last month. The initial payment was reportedly delayed due to US sanctions on Russia.

The S-400 deal was opposed by the US and Trump administration had threatened to impose sanctions on countries that are acquiring weapons and military hardware from Russia.

Although India has Akash missiles and has made significant progress in its BMD program (Ballistic Missile Defence Program), the air defence in the 400 km to 25 km range remained a concern.

"We did not have anything (in terms of air defence) between 400 km and 25 km. This is a system which can take on the enemy from 30 km to 400 km. Then you are also buying Israeli Barack 8 systems which have a range of 70 km extendable up to 100 km. So, you will have a layered air defence to take on threats from China and Pakistan," said Major General P K Sehgal had said.

It is completely a game changer as far as Indian sub-continent is concerned," he further said.

The reason why Major General P K Sehgal is calling the deal a game changer is because of the multiple intercept missiles the S-400 system can fire. The S-400 supports four different missiles - the very long-range 40N6E-series (400 km), the long-range 48N6 (250 km), the 9M96e2 (120 km) and the short-range 9m96e (40 km). It can prioritise the incoming attacks and take action appropriately.

The system has a multi-function radar, autonomous detection and targeting systems, anti-aircraft missile systems, launchers besides a command and control centre.

The two other major air defence systems with India are Spyder and Barak-8. While Spyder has a range of 15 kilometres, Barak-8, a joint project of the DRDO and the IAI, is said to have a longer range of at least 70 kilometres.

Important Things That You Must Know About S-400 Missile System:

1. S-400 Triumf is one of the world's most advanced air defence systems that can simultaneously track numerous incoming objects - all kinds of aircraft, missiles and UAVs - in a radius of a few hundred kilometres and launch appropriate missiles to neutralise them

2. The S-400 was developed as an upgrade of the S-300 series of surface-to-air missile systems. The S-400 Triumph air defence system integrates a multi-function radar, autonomous detection and targeting systems, anti-aircraft missile systems, launchers, and command and control centre

3. The S-400 air defence missile system uses four new missile types in addition to the missiles of the S-300PMU system. The S-400 Triumph also launches 9M96E and 9M96E2 medium-range ground-to-air missiles

4. Designed for direct impact, the missiles can strike fast-moving targets such as fighter aircraft with a high hit probability. The highly automated S-400 has radars that can pick up an incoming object up to a 1,000 kilometres away, track several dozen incoming objects simultaneously, distribute the targets to appropriate missile systems and ensure a high success rate

5. It has been in service with the Russian Armed Forces since 2007. The S-400 was described by The Economist in 2017 as "one of the best air-defence systems currently made."

6. It has been in service with the Russian Armed Forces since 2007. The S-400 was described by The Economist in 2017 as "one of the best air-defence systems currently made."

7. S-400's comparable missile system, US-made MIM-104 Patriot, is losing market to the Russian weapon system across the globe. The S-400 is two-times more effective than previous Russian air defence systems and can be deployed within five minutes