 As part of the Cold War operation, they were deployed in the Arabian Sea and later embarked on being deployed on long-range mission to test depth and submerged endurance in Indian Ocean.The Agosta-90B-class submarines is an improved version with modern systems, better battery with longer endurance, deeper diving capability, lower acoustic cavitation and better automatic control (reducing crew from 54 to 36).It can be equipped with the MESMA air-independent propulsion (AIP) system.