CCDTS or Command Clearance Diving Teams are EOD guys who work under water. Let that sink in fellas.
Doing EOD work on land itself is a nut job.
Doing that under water means these guys sink in cause their balls are of steel and fucking heavy!
Why because the shockwave generated by an underwater explosion travels faster and with less energy dissipation compared to an explosion in the air. It causes rapid and intense overpressure, which can damage structures, crush submerged vessels, or injure marine life and divers nearby even if they are at a distance away from blast radius where had they been on land, they'd not get scratched. Unlike on land, where air can compress and provide some cushioning, water does not compress easily. This rigidity confines the energy of the explosion, concentrating it. So underwater demolion teams or clearance diver teams have the risk of not only been blown up by explosives if things go sideways but incase they're injured and cant make it up to surface for a boat or helo to extract them...sooner or later they'll drown while already having suffered a concussion. Also CCDTs have an offensive role too. They go underwater and plant explosive mines and also use explosives to remove obsticals on beach that might hinder a beach assault. You can say they are basically Sappers with a diving certificate
Acc to Cdr Vijay Rawat, all MARCOS were CDs, and some SDs before 2017 when the course changed to Combat diving course more suitable for MARCOS requirements.