Johannesburg - Three women have apparently overdosed on an unknown substance at a mall in Randburg, Johannesburg, on Thursday, paramedics said.Paramedics found them on the floor near the entrance of the mall, on Bram Fischer Drive, ER24 spokesperson Werner Vermaak said."One of them was in a critical condition. Paramedics initiated advanced life support on her in order to assist her with her breathing."The other two were responsive, but unable to say what had happened."Bystanders flocked to the entrance of the mall and explained that the area is well-known for illicit substances," said Vermaak.The three were taken to Helen Joseph Hospital.