The woman, who is separated from her husband and searching for a job, was spotted by a police patrol van near a dust bin in an unconscious state.
She was rushed to the Guru Teg Bahadur hospital where her condition is stated to be out of danger.
Police said the woman had asked Yashdev, an accused, to help her in getting a job and on Monday evening, he called her in the pretext of offering her a job.
When she reached, three of his friends joined him and allegedly offered her drinks laced with sedatives, they said quoting the woman. Yashdev was arrested after a medical examination confirmed rape.
Another case was reported from Anand Vihar area where an eight-year-old girl was raped by an unidentified person on Wednesday morning. The victim was found lying in a pool of blood and she is undergoing treated in a hospital.
A 14-year-old girl was raped allegedly by a 16-year-old boy at knife-point in Gokulpuri area yesterday. In the fourth incident reported from Ranhola on Tuesday, a 12-year-old girl was sexually assaulted by her relative.