They filed their nomination papers with Assembly Secretary AMP Jamaludeen, who is the Returning Officer for the biennial elections.
A posse of DMK leaders including MK Stalin, Durai Murugan, TR Baalu and a number of DMK MLAs were present when Bharathi and Elangovan filed their nominations.
Bharathi, an advocate and DMK's organisation secretary, had been chairman of Alandur Municipality in the past, while Elangovan is a former Lok Sabha MP who had represented North Chennai constituency from 2009-14.
AIADMK's Navaneethakrishnan, A W Rabi Bernard and P H Paul Manoj Pandian and DMK's K P Ramalingam and S Thangavelu and former Union Minister and Congress leader Sudarsana Natchiappan are those who will be retiring in June.
Out of the six members, Navaneethakrishnan was elected in 2014 and others in 2010. He filled the vacancy caused by the disqualification of DMK's T M Selvaganapathi.