The mayor of Johannesburg Herman Mashaba on Monday resigned from his position and quit the main opposition party, the Democratic Alliance, over its approach to racial inequality.

Mashaba’s resignation was prompted by the election of former party leader Helen Zille as the DA’s federal council chairperson on Sunday.

Last week, Mashaba had threatened to quit the party if it was taken over by what he termed as right-wing elements.

Zille, a former journalist and anti-apartheid activist, courted controversy in March 2017 after claiming on social media that there were some positive aspects to colonialism.

She, however, apologised for her comments and subsequently relinquished her party leadership positions.

“I cannot reconcile myself with people who believe that race is not important in their discussion of inequalities,” Mashaba said during a press conference.

Mashaba, 60, was a senior politician in the DA, a historically white party. He was elected in 2016 as the first mayor from outside the ruling African National Congress since the end of apartheid in 1994.

“The election of Zille as the chairperson of the federal council represents a victory for people in the DA who stand diametrically opposed to my beliefs and value system,” Mashaba said.

Mashaba also cited the undermining and criticism of his “pro-poor agenda” by the party.

“Some members of the DA caucus in Johannesburg have suggested that we prioritise the needs of suburban residents above providing dignity to those forgotten people who remain without basic services 25 years after the end of apartheid,” Mashaba said.