As the proverb, slow and steady wins the race, India is working towards making its national capital more impregnable against military or 9/11-like terror attacks from aircraft, missiles and drones.

The measures underway involve getting a new missile shield to replace older air defence systems, re-configuring the VIP no-fly zone and refining the protocol to shoot down rogue planes.

Defence minister Nirmala Sitharaman has signed the 'acceptance of necessity (AoN)' for the acquisition of the National Advanced Surface to Air Missile System-II (NASAMS-II) worth around $1 billion from the US.

Simultaneously, as component of the overall Delhi Area Air Defence Plan, work is on to further realign the 'VIP-89 area' over New Delhi, which includes Rashtrapati Bhavan, Parliament, North and South Blocks, as well as reduce the decision-making loop to shoot down planes that may have been captured or commandeered for use as "missiles against strategic targets", say sources.

The NASAMS, armed with three-dimensional Sentinel radars, short and medium-range missiles, launchers, fire-distribution centres and command-and-control units to quickly detect, track and shoot down multiple airborne threats, is part of the air defence network guarding Washington. It is also used in several NATO countries. Besides the US national capital region, Israeli cities and Moscow too have their personal missile defence systems.

India’s progress to acquire NASAMS comes even as DRDO is in the final stages of developing its two-tier ballistic missile defence (BMD) shield, which is meant to track and destroy nuclear missiles both inside (Endo) and outside (Exo) the earth's atmosphere.

Sources say that once the Phase-I of the BMD system is operational, it will be deployed to protect cities like Delhi and Mumbai from long-range missiles with a 2,000-km strike range. The NASAMS, in turn, is prepared towards intercepting cruise missiles, aircraft and drones.

The defence ministry, however, has kept the $2 billion procurement of 24 MH-60 ‘Romeo’ helicopters, with their associated weapons, spares and training packages, from the US pending till the inaugural 'two-plus-two' dialogue between the two countries here on 6 September.

India wants to "assess the US response" on different issues, including its punitive sanctions regime under the Countering America's Adversaries Through Sanctions Act (CAATSA). That tries to prevent countries from buying Russian weapons or Iranian oil, before granting AoN to the helicopter plan as well.

The AoN for the helicopters, which are used to detect, track and hunt enemy submarines, has been deferred till September. Earlier also, it was not covered in the DAC after US abruptly cancelled the two-plus-two dialogue slated for July. Indian sources later told that this was due to US’s upcoming engagement with North Korea.

The US is moving towards allowing the waiver to India from CAATSA but it’s not yet confirmed. India wants to finalise the Rs 39,000 crore deal for five top-tier S-400 Triumf air defence missile systems from Russia later this year without the threat of financial sanctions from the US.

India has maintained both the proposed procurement projects, the NASAMS as well as the naval helicopters, for government-to-government contracts through the US foreign military sales (FMS) programme.

The FMS programme is considered "faster and cleaner" than the global tender process, with the AoN, accompanied by "letters of offer and acceptance" being negotiated before sealing the final contract. The US, of course, is eager to bag more deals, having notched military sales worth $15 billion to India since 2007.

The Indian Navy, in turn, is desperate to acquire multi-role helicopters, armed with radars and sonars as well as missiles, torpedoes and depth charges, because it has virtually run out of them. The 140-warship force has just about a dozen old Sea King and 10 Kamov-28 anti-submarine warfare helicopters.

According to media reports, Admiral Sunil Lanba, in a lecture on 27 July said, "The Navy is staring at critical capability gaps with respect to minesweepers, integral multi-role and utility helicopters, and conventional submarines." As part of the long-term 'Make in India' projects, the Navy is looking to acquire 123 multi-role helicopters and 111 armed light utility choppers.