Deepti Chauhan, who stayed in Alaknand Co-operative Society building, went to the seventh floor and flung her son from there, before jumping herself, said Additional Police Commissioner (North) Ramrao Pawar.
The mother and son were rushed to nearby Bhagwati hospital where they were declared dead on admission, he said.
The reason behind the suicide is not yet clear, Pawar said, adding that the family members of the victim were being questioned on the incident.
Last month, a 32-year-old chartered accountant flung her two children to their death and then jumped herself from the 19th floor of a building in suburban Malad here.
Deccan Herald is on WhatsApp Channels| Join now for Breaking News & Editor's Picks