On  the preoperative day, patient’s airway will be assessed, which includes Mallampatti grading, Thyromental Distance, Sternomental Distance, height,weight, neck mobility. Ratio of  height to thyromental distance ( RHTMD)and ratio of height to sternomental distance (RHSMD)will be calculated. In the operation theatre, the baseline vitals of the patient like spo2,PR, BP,ECG will be recorded.Then patients will receive premedication with midazolam and Glycopyrrolate followed by preoxygenation with 100% oxygen.Anesthesia will be induced with propofol 1- 2mg/kg and muscle relaxation with vecuronium 0.1mg/kg as done routinely. Intubation will be carried out by an anesthesiologist with more than 5 years experience and who is blinded to the study.The glottis exposure on direct laryngoscopy will be graded as per routine. Intubation will be considered difficult if view on laryngoscopy is Cormack Lehane 3 or 4, >3 attempts at intubation, duration > 10min,or if stylets,bougie, video laryngoscopy or fibreoptic bronchoscope used.The preoperative airway assessment data and findings during intubation will be assessed and correlated to establish the incidence of difficult intubation. The ability of RHTMD and RHSMD to predict difficult airway preoperatively in patients actually     found to have difficult laryngoscopy and intubation will also be studied.