Two regiments of Indian army are equipped with Arjun Mark 1 main battle tanks.

Two regiments of Indian army are now equipped with the Indian-made Arjun Mark 1 main battle tank (MBT), currently 124 Arjun Mark 1 have already been produced. Each tank regiment has 62 main battle tanks. The Arjun Mark 1 is a main battle tank developed by India's Defense Research and Development Organization (DRDO), for the Indian Army. The Arjun Mark 1 is presented at DefExpo 2018, the Defense and Security Exhibition in Chennai (India) on the booth of DRDO.

The Arjun Mark 1 MBT  main battle tank of Indian army at DefExpo  2018, the Defense and Security Exhibition in Chennai, India. April 11, 2018. (Picture source Army Recognition)

The first 45 main battle tanks Arjun Mark 1 were delivered to the Indian army between August 2004 and May 2009. More than 100 tanks have been delivered to the Indian Army by June 2011. After extensive field evaluations and tests, the tank entered service with the 75th Armoured Regiment on 12 May 2011.

The main armament of the Arjun Mark 1 consists of one 120 mm main rifled gun able to fire indigenously developed armour-piercing fin-stabilized discarding-sabot ammunition. Second armament includes one PKT 7.62 mm coaxial machine gun, and one NSVT 12.7 mm machine gun mounted on the commander hatch. This machine gun can be used to protect the tank against aerial threats as helicopter and low flying aicraft.

The Arjun Mark 1 has a crew of four including driver seated at the right front of the hull. Commander, gunner and loader are located in the turret. The turret and glacis are protected with "Kanchan" ("gold") modular composite armour, which derived its name from Kanchan Bagh, Hyderabad, where the Defence Metallurgical Research Laboratory (DMRL) is located. Kanchan is made by sandwiching composite panels between Rolled Homogenous Armour (RHA). This helps in defeating APFDS and HEAT rounds.

The Arjun Mark 1 is motorized with a German MTU engine coupled to a French Renk transmission. The water-cooled engine generates 1,400 hp. and is integrated with an Indian turbocharger and gearbox with four forward and 2 reverse gears. The Arjun Mark 1 can run at a maximum road speed of 67 km/h and 40 km/h in off-road conditions. It has a maximum road cruising range of 600 km.

The computerized fire control system aboard Arjun has been jointly developed by DRDO with Israeli company Elbit. The Fire Control System is stabilized on two axes, and with an extremely high hit probability (design criteria call for a greater than 0.9 Pk) replaces an earlier analogue one, which had problems due to its inability to function under the harsh desert conditions. The combined day sight from Bharat Electronics Ltd. and the thermal imager (formerly from Sagem, now reported to be from El-Op) constitute the gunner's primary sight.