Sindhuratna is headed back to the Mumbai shore after it was forced to surface in the wee hours when smoke was detected on board. Sources in the navy confirmed the incident and said few sailors, who were in the compartment were shifted to hospital after they fell unconscious due to the suffocation from smoke.
In August last year, another navy submarine, the INS Sindhurakshak sank in the Mumbai harbour after an explosion took place on board, killing 18 navy personal including three officers.
The submarine was being sea tested after a refit, around 50 km off the Mumbai coast when the smoke was detected.
The submarine was carrying no weapons or ammunition but it was carrying a senior submarine officer of the western naval command.
A board of inquiry under a senior officer has been ordered to ascertain the reason.