Former City of Johannesburg mayor Herman Mashaba says his decision to leave the DA was cemented on Wednesday when at least one DA councillor voted for the ANC's Geoff Makhubo to succeed him as the metro's number one citizen.Makhubo received support from 137 councillors, giving him more than the 50% plus one majority needed to win the vote. The DA was represented by Funzela Ngobeni, who served as a member of the mayoral committee under Mashaba.READ | DA on councillor who voted for ANC's Geoff Makhubo: 'It's an outright betrayal, but we won't go on a witch hunt'While the vote was held in secret, it's been widely speculated that at least one DA councillor voted for Makhubo based on the number of seats each party has in council. "The fact that some DA councillors elected to vote for Makhubo over their own candidate, demonstrates why I had to leave the DA. The DA of today is clearly not the DA that I joined - not when they support an allegedly corrupt person," the former mayor said in a statement on Thursday morning.READ | Geoff Makhubo: Meet Joburg's tainted mayorHe said the fact that his former coalition partners abandoned the multi-party government "speaks clearly to the fact that I am not alone in my view"."They did not see a prospect of working with the DA in a coalition that is open, engages with different solutions to our complex problems, and is willing to set aside differences in the interests of the residents," the former businessman added.Mashaba the "considerations were all about personal and political benefit, and not about the residents of Johannesburg".While Mashaba claims he left the DA before he was pushed out, the party denies it ever intended to remove him as mayor or wanted him to leave.