Five men have pleaded not guilty to charges they gang raped and murdered an Indian trainee physiotherapist.
The case has led to a shake-up of laws against sexual crimes after there were protests over the rising number of attacks on women.
The men were read 13 charges including murder, which carries a maximum penalty of death.
They left after 15 minutes.
"After the judge read out the charges, the five pleaded not guilty and walked out" said AP Singh, a lawyer defending two of the accused, Vinay Sharma and Akshay Thakur.
Mr Singh said the next hearing will be held on 5 February, when the prosecution will call three witnesses to the formal start of the trial.
A sixth person police say was part of the gang that attacked the woman and her friend is a juvenile and will be tried separately.
Police say the gang lured the 23-year-old physiotherapy student onto a bus, where they repeatedly raped and assaulted her with a metal bar before throwing her bleeding onto a highway.
She died of internal injuries two weeks later.