Chennai, May 9 (UNI) The Directorate of Enforcement (ED), Chennai Zonal Office,has unearthed a deep-rooted and systemic corruption network across key Tamil NaduGovernment departments during recent raids and seized unaccounted cash to the tuneof Rs 4.73 crores. In a statement on Friday, the ED said it had conducted search operations across Chennai and Vellore on May six under the provisions of the Prevention of Money Laundering Act (PMLA), 2002 at 16 premises associated with certain officer and various prominent consultants for Government departments of Tamil Nadu.