India's indigenously-constructed nuclear submarine INS Arihant has reportedly suffered a major damage due to human error and been under repair for almost 10 months. According to the local news outlet, the outer hatch of the submarine is believed to have been left accidentally open, leading to ingress of seawater into the vessel. 

Commissioned into service in August 2016, 6000-ton nuclear-powered submarine is armed with 12 K-15 missiles with a range of 750 km, which will later be upgraded K-4 missiles with an extended range of 3500 km.