“In this moment of sadness, we lower our flags in homage to this great citizen of the city and commit to ensure that her name is inscribed on the roll of those who shaped our consciences as we take the country forward,” mayor Kgosientsho Ramokgopa said in a statement.
Mahlangu, a resident of Mamelodi, east of Pretoria, died at Steve Biko Academic Hospital on Wednesday.
Her son Solomon Kalushi Mahlangu was a member of the ANC’s armed wing Umkhonto we Sizwe (MK).
He was hanged at the Pretoria Central Prison on April 6, 1979.
Solomon had been charged for the murder of two white civilians in Johannesburg two years earlier.
City of Tshwane spokesman Blessing Manale said consultations with the Mahlangu family and the ANC to finalise funeral arrangements were under way.
The arrangements included a women’s prayer service, a memorial service at the City Hall and a parade by the Tshwane metro police.
The dates on these events and that of the funeral would be finalised as soon as details had been concluded, said Manale.