Defence production in India is categorised into four key organisational types to capture the structural dynamics and sectoral contributions within the defence manufacturing ecosystem. Old Defence Public Sector Undertakings (Old DPSUs) are long-established government-owned enterprises that have historically led India’s defence production. Examples include Hindustan Aeronautics Limited (HAL), Bharat Electronics Limited (BEL), and Bharat Dynamics Limited (BDL). These units form the backbone of India’s indigenous defence capabilities, primarily engaged in manufacturing aircraft, electronics, missiles, and armaments. New Defence Public Sector Undertakings (New DPSUs) are more recently established or restructured from former Ordnance Factory Boards or other defence units, with a focus on modernisation, efficiency, and self-reliance. Their creation aligns with India’s Atmanirbhar Bharat (self-reliant India) initiative, aiming to infuse innovation and competitiveness into the public defence sector. Other Public Sector Undertakings/Joint Ventures include collaborative defence initiatives between Indian PSUS or between PSUS and foreign/domestic entities. These joint ventures facilitate technology transfer, co-development, and broader industrial participation in defence manufacturing. Defence Private Companies include those private sector firms that engage in defence production, including both large conglomerates and specialised MSMES. Their increasing involvement reflects policy reforms promoting private sector participation, FDI, and Make-in-India objectives for defence self-sufficiency.