India's Security Architecture: CDS, the Department of Military Affairs, and the CAPFs

India's security establishment runs on two separate institutional tracks that students routinely mix up. External defence runs through the Ministry of Defence, the three Services, and since 2019 through a new tri-service layer built around the Chief of Defence Staff (CDS) and the Department of Military Affairs (DMA). Internal security runs through the Ministry of Home Affairs and its seven Central Armed Police Forces (CAPFs), a separate chain of command entirely. UPSC's "various security forces and agencies and their mandate" questions almost always turn on knowing exactly where one track's authority ends and the other's begins.

The Chief of Defence Staff: what the post actually is

The Union Cabinet approved the creation of the CDS post on 24 December 2019, in the rank of a four star General, with salary and perquisites equivalent to a Service Chief. The decision followed the Prime Minister's 15 August 2019 Independence Day announcement that India's "entire military power will have to work in unison."

The CDS wears two hats. As Permanent Chairman of the Chiefs of Staff Committee (COSC), a role that used to rotate among the three Service Chiefs by seniority, the CDS acts as the single point of military advice. As head of the newly created DMA, the CDS also functions as its Secretary within the Ministry of Defence.

The trap: advice, not command

The single most tested line in the Cabinet decision is this one: the CDS "will not exercise any military command, including over the three Service Chiefs, so as to be able to provide impartial advice to the political leadership." The CDS functions as the Principal Military Adviser to the Raksha Mantri on tri-Services matters, while each Service Chief continues to advise the Minister on matters concerning their own Service alone. A question that describes the CDS as commanding the Army, Navy, or Air Force, or as outranking the three Chiefs operationally, is testing exactly this distinction, and getting it wrong.

Department of Military Affairs: functions and scope

The DMA became operational on 1 January 2020, created as the fifth department within the Ministry of Defence (alongside Defence, Defence Production, Defence Research and Development, and Ex-Servicemen Welfare). Under the Second Schedule to the Government of India (Allocation of Business) Rules, 1961, the DMA was allocated:

• The Armed Forces of the Union: Army, Navy, and Air Force.
• The Integrated Headquarters of the Ministry of Defence (Army HQ, Naval HQ, Air HQ, and Defence Staff HQ).
• The Territorial Army, and works relating to the Army, Navy, and Air Force.
• Procurement exclusive to the Services, excluding capital acquisitions, which stay with the Department of Defence.

Beyond these allocated subjects, DMA's mandate covers promoting jointness in procurement, training, and staffing across the Services; facilitating the restructuring of Military Commands, including towards joint or theatre commands; and promoting indigenous equipment. In practical terms, 23 sections and around 160 civilian officers and staff were transferred from the Department of Defence to the newly created DMA, a fact confirmed in a written Rajya Sabha reply on 3 February 2020.

What sits directly under CDS command

As Permanent Chairman of COSC, the CDS also directly administers tri-service organisations, and specifically, tri-service agencies, organisations, and commands relating to Cyber and Space are placed under CDS command. The CDS additionally sits as a member of the Defence Acquisition Council (chaired by the Raksha Mantri) and the Defence Planning Committee (chaired by the National Security Adviser), and acts as the Military Adviser to the Nuclear Command Authority. The CDS was also mandated to bring about jointness in operations, logistics, training, and support services across the three Services within three years of the first CDS assuming office, a concrete timeline worth remembering alongside the functional list.

The Central Armed Police Forces: the internal security layer

Separately from all of this, the Ministry of Home Affairs administers seven Central Armed Police Forces: the Assam Rifles (AR), Border Security Force (BSF), Central Industrial Security Force (CISF), Central Reserve Police Force (CRPF), Indo-Tibetan Border Police (ITBP), National Security Guard (NSG), and Sashastra Seema Bal (SSB). These are distinct from the Armed Forces under the Ministry of Defence and from state police forces, which fall under the State List.

Their mandates differ sharply by force. AR, BSF, ITBP, and SSB are primarily border guarding forces, each assigned to a specific frontier (BSF along the Pakistan and Bangladesh borders, ITBP along the China border, SSB along the Nepal and Bhutan borders). CISF guards industrial undertakings, critical infrastructure, and airports. CRPF is India's largest CAPF and the principal force supporting state governments on law and order, internal security, and counter-insurgency operations. NSG is a specialised counter-terrorism and hostage-rescue force, deployed only for specific high-risk operations rather than routine duty.

Assam Rifles: the exception worth remembering

Assam Rifles is the one CAPF with a genuinely dual reporting line: its administrative control sits with the Ministry of Home Affairs, while its operational control sits with the Indian Army under the Ministry of Defence. MHA decides recruitment, pay, and infrastructure; the Army decides deployment, postings, and operational tasking. No other CAPF splits control this way, which is precisely why it recurs as a standalone statement-based question.

Quick revision points

• CDS: four-star General rank, created by Cabinet decision 24 December 2019; Permanent Chairman of COSC (a role that used to rotate); explicitly does not exercise military command over the Services or the three Chiefs.
• DMA: operational from 1 January 2020, the fifth department of the Ministry of Defence, CDS as Secretary; handles the Army/Navy/Air Force, Integrated Service Headquarters, Territorial Army, and Service-specific procurement (not capital acquisitions).
• CDS additionally commands tri-service Cyber and Space agencies, sits on the Defence Acquisition Council and Defence Planning Committee, and advises the Nuclear Command Authority.
• Seven CAPFs under the MHA: Assam Rifles, BSF, CISF, CRPF, ITBP, NSG, SSB, each with a distinct mandate (border guarding, installation security, internal security, or counter-terrorism).
• Assam Rifles alone has dual control: administration under MHA, operations under the Army/MoD.

Once the CDS versus COSC versus Service Chief distinction is clear, along with each CAPF's mandate, practise the statement-based questions UPSC builds around exactly these boundaries.