there were no "90,000"soldiers to surrender..the army component was some 55,000; the indians included civilians in their totals see the detailed breakdown...thus 57,400 regulars only, 16,500 militia=74,000 approx.
55,692 were Army, 16,354 Paramilitary, 5,296 Police, 1000 Navy and 800 PAF.[72] The remaining prisoners were civilians – either family members of the military personnel or collaborators (razakars). The Hamoodur Rahman Commission report instituted by Pakistan lists the Pakistani POWs as follows: Apart from soldiers, it was estimated that 15,000 Bengali civilians were also made prisoners of war.[73]
Branch Number of captured Pakistani POWs
Army 54,154
Navy 1,381
Air Force 833
Paramilitary including police 22,000
Civilian personnel 12,000
Total: 90,368
Indo-Pakistani War of 1971 - Wikipedia, the free encyclopedia
Niazi was more incompetent than treacherous...
the main reason for the surrender was that the
Indians had threatened to turn the muktis [and the indian soldiers masquerading as muktis] on the east pakistani civilians....[razakars their families, biharis and other unarmed muslims who might be loyal to pakistan or had stayed neutral]...the subsequent pak govt of zulfiqar deliberately buried this fact in order to humiliate the defence forces further and in order to permit him to sell pakistan's interests in Simla "agreement" [more like capitulation] ...he had already amde sure that any hope of retaining east paksitan was lost [idhar hum udhar tum] may he been cursed forever....