There is a detatchment of MARCOs in Mumbai at the naval base. The Government of Mumbai reached out to the Navy a few hours into the attack for their services and one team of 8-10 operators was deployed (including EOD techs and snipers), their work is documented:
Indian Navy MARCOS: The unsung heroes of 26/11 Mumbai attacks
The NSG arrived not 24 hours later but 10 hours and their side can be understood:
1) Point taken, the MARCOs' did not have sufficent CQB training pre-26/11, this was identified and coreccted within the unit.
2) 72 hours is a BS figure that denotes the very first attack (not at a hotel) on the night of 26/11 to the offical Render Safe procedure of the very last (of upwards of 10 sites) being completed by the NSG.
3) Their (MARCOs') role was not to clear any building but to pin down the terrorists and once the NSG arrived from Delhi the MARCOs played very little part in the subsequent operations. To understand more about the role the MARCOs played read:
Indian Navy MARCOS: The unsung heroes of 26/11 Mumbai attacks
The primary focus of the NSG (India's dedicated counter terror/intervention force) is preserving innocent life and once they arrived in Mumbai (around 10 hours after the attacks begun) not a single innocent died so they were succesful in their primary objective. Once all the hostages and civlians were safe and rescued the NSG went about hunting down the terrorists.
