The adult patients posted for major surgery under general anesthesia will be included in the study, patients will be allotted randomly to either Group P (Propofol) or Group D (Dexmedetomidine). In the Operation Room (OR) monitoring Electrocardiography (ECG), Pulse Oximetry (SPO2), Noninvasive Blood Pressure (NIBP), End tidal Carbon di oxide (ETCO2) and Bispectral Index (BIS) Covidien, will be attached to all patients. In both groups Anesthesia will be induced with midazolam 1mg, Fentanyl 1mcg /kg-1, Morphine 0.1mg/kg-1 and Neuromuscular blocking agent Atracurium 0.5 mg/kg-1. Oral Cuffed Endotracheal Tube (ETT) will be placed in the trachea. In Group P - Anaesthesia will be maintained with medicated Air/Oxygen (O2) with Fractional Inspired Oxygen (FiO2 50%), Sevoflurane and Propofol Infusion to maintain BIS between 40-60. In Group D anesthesia will be maintained with Medicated Air/Oxygen (FiO2 50%), Sevoflurane and Dexmedetomidine infusion to maintain BIS between 40-60. Intraoperatively monitoring of vitals, BIS numerical value, Minimum Alveolar Concentration (MAC) Value for Sevoflurane, Expired concentration of Sevoflurane and rate of infusion of Propofol/Dexmedetomidine will be noted every 30 minutes. Intraoperative decrease in Mean Arterial Pressure (MAP) < 60 mmHg, Heart rate (HR) < 50, SPO2 < 90 % will also be noted. At the end of surgery total dosage of Propofol/Dexmedetomidine and total amount of Sevoflurane consumed will be calculated. At the end of surgery neuromuscular blockade will be reversed. Total Duration of anesthesia will be noted. On emergence from anesthesia any episode of acute delirium will be recorded. Time from end of anesthesia to eye opening will be noted in both the groups. Neuropsychological Test consisting of Letter Digit Substitution Test, Trail Making Test Part A, Part B, Stroop Colour Word Test, Visual Verbal Learning Test will be performed 24 hours prior to surgery and on postoperative day 3, day 7.