Dr K Vijayakarthikeyan, Commissioner, Corporation, handed over the certificate to Natarajan, representing 41st ward in the council, official sources said.
Of the 20 councillors in the zone, 14 AIADMK councillors attended the electoral procedure, while DMK and CPI members boycotted.
The post was vacant following resignation of P Rajkumar, who had contested and won the post of Mayor some months ago.
