Deputy Police Commissioner Suman Nalwa said police submitted charges against five suspects in court in Saket, a southern district of Delhi where the attack occurred, CNN reported.
Nalwa said authorities were waiting for results from a bone marrow test before deciding whether to charge a sixth suspect, believed to be a minor, as a juvenile or an adult. The test was conducted to determine the suspect's exact age.
The Dec. 16 attack on the 23-year-old woman, who died from her injuries Saturday, has prompted debate over the way the country handles sexual assaults and the treatment of women in Indian society.
The men are accused of assaulting the woman and her male companion on a private bus, robbing them then throwing them off the bus, police said. The male companion eventually was discharged from a local hospital.
The woman was flown to a Singapore hospital, where she died, for specialized treatment.
Street protests, which have been a daily occurrence since the woman's death, were held again Thursday in the Indian capital.
Authorities said they plan to seek death penalty for the five defendants. If the sixth person is confirmed to be a minor, he could be sent to a children's home for a maximum of three years.
Lawyers who make up the executive board of the Saket Bar Association Wednesday said they wouldn't represent any of the accused because of the nature of the crime, and have encouraged its 7,000 members to follow their lead.
The accused could be represented by attorneys from other districts or ones appointed by the court, CNN said.