Technical glitches forced the Army to ground nearly 75% of its 124 indigenous Arjun Mark 1 battle tank fleet. Developed by Defence Research and Development Organisation (DRDO) and produced by Heavy Vehicles Factory at Avadi, almost 55% of the tank is made of imported components (not available any more). The Arjun Mark 1 has still not been cleared by the Army for combat because it weighs a whopping 62 tonnes. The indigenous Arjun tank project had begun in 1974 to replace Russian T-54 tanks but more than 1,600 Russian T-72 tanks are still in operation!