India and Russia signed the $5 billion S-400 Air Defence Missile System (ADMS) for "national interest" on October 5, after a long talk between Prime Minister Narendra Modi and Russian President Vladimir Putin. The agreement was at the 19th India-Russia Annual Bilateral Summit. The contract was signed by the Joint Secretary of Land Systems and the Director General Rosoboronexport (ROE) of Russia just before the bilateral meeting between Prime Minister Modi and President Putin had begun. India has bought 40 launchers and about 1,000 missiles. 70% of these missiles are of very long range (400 km-350 km) cluster and the others have lower ranges (300km-250km). The S-400 surveillance radar with the range of 600 km and 360 degree coverage can track 70 targets. This is known as Russia's most advanced long range surface-to-air missile defence system. Earlier, for the protection of high value targets, the Air Headquarters had purchased the United States’ National Advanced Surface to Air Missile System (NASAMS). At that time it was an important decision for the country’s defence sector. But now, while the S-400 can destroy hostile ballistic missiles, NASAMS cannot do so. It can only destroy cruise missiles and other aerial platforms.
The military requirement of the S-400 Air Defence Missile System (ADMS) programme has been an important matter for India, but the political situation for the same was in a dilemma for years. The government of India came close to signing the contract several times, but always it had to step back at the last moment. This was a matter of negotiation that precedes Countering America’s Adversaries Through Sanctions Act (CAATSA) by several years. It was introduced by the US Congress on arms purchases from Russia. Washington has always insisted on its allies waiving transactions with Russia. The US had warned earlier that the S-400 missile defence system that India wanted to buy would be a centre area to implement punishing sanctions for any undertaking doing business deals with Russia. But India wanted the long-range missile systems to tighten its air defence mechanism, particularly along the nearly 4,000 km long Sino-India border.