The Delhi-class destroyers are guided-missile destroyers of the Indian Navy. Three ships of this class are in active service. The Delhi-class vessels were the largest vessels to be built in India at the time of their commissioning. The ships were built by Mazagon Dock Limited (MDL) at a cost of each. Development The design and development of the ship class began as "Project 15" in 1980. Initially, the ships were planned to be follow-on frigates of the with the addition of RBU-6000 ASW rocket launchers and gas turbine propulsion. A Soviet offer in 1983 for reversible gas turbines and modern weapon systems forced a redesign of the ships from 3,500 tonne frigates to 6,300 tonne destroyers. Directorate of Naval Design completed the design around the mid 1980s. Model tests were carried out at SSPA, Sweden in 1985 and parallelly at Krylov Institute, Soviet Union in 1986. Severnoye Design Bureau provided design inputs for weapons and propulsion packages. The mutual interface suppression system for electromagnetic compatibility was supplied by the Soviets. The break-up of Soviet Union affected the supply of weapon systems, contributing to a three-year delay in the construction of vessels. Design and description Delhi class has been described as a stretched with some elements incorporated from Godavari-class frigates and s. The fore funnel is placed on the port side, while the aft funnel is placed on the starboard. The propulsion system consists of two Zorya-Mashproekt M36E gas turbine plants driving two controllable-pitch propellers. Each gas turbine plant comprises two DT-59 reversible gas turbines connected to an RG-54 gearbox in a combined gas and gas system and is placed in a separate engine room. The vessels are equipped for operation in a nuclear, biological and chemical warfare environment. Delhi-class vessels are fitted with flag facilities, enabling them to act as command unit in task groups. features better air conditioning facilities to correct heat dissipation issues encountered while operationalising . Armament For air defence role, Delhi class is fitted with 9K-90 Uragan (NATO: SA-N-7 Gadfly) air-defence system comprising a pair of 3S-90 single-arm launchers and 9M38M1 Shtil missiles. One launcher is installed forward of the bridge and the other atop the dual helicopter hangar. Each launcher carries a 24 missile magazine for a total of 48 rounds. The missiles have range and feature semi-active radar homing. MR-775 Fregat-MAE (NATO: Half Plate) radar provides target designation and six MR-90/3R-90 Orekh (NATO: Front