All those keyboard warriors who are saying that it was already on surface and snorkeling, so whats the big deal and it wanted to show it self, have no idea whatsoever about submarine operations. So cut the bullshit excuses and accept the fact that it was caught.
"NO SUB EVER WANTS ITSELF TO BE SEEN ON THE SURFACE", no matter what.
What actually happened cannot be shared, but the Kalvari class sub was located and then forced to come to periscope depth. After it came on surface this video was made with an IR camera, which gives the time and exact location of the interception.
What happened after that is also confidential, but when a submarine is exposed, it basically has to go back as the mission it was sent on has been compromised.
A submarine is designed to operate unseen, and even during peace time/transits/exercises it remains unseen. It is NOT designed to sail on the surface of the water.
The biggest blunder they did, was to send the Kalvari class, probably they were testing it's capability, but they exposed it's acoustic and magnetic signatures, which are basically fingerprints for every vessel and are kept a secret, and now we have them.
The CO of the sub will definitely be sacked due to his incompetence and tactical decision making.