Service Delivery Excellence model ensures standardized citizen-facing service norms and centralized single-window submissions with acknowledgements. The SEVOTTAM model establishes a centralized 'Single Window' receipt and disposal mechanism for written communications with immediate counter acknowledgement issuing a unique diary number and deadlines for postal acknowledgements. It sets explicit Citizen's Charter service norms-timelines for acknowledgements, decisions, registrations, refund and drawback disposals, export/import clearances, document release, audit notices and grievance handling-and provides feedback channels and designated grievance officers to ensure accountability and continuous service improvement.