The taxi driver reportedly fled from the accident site. He was apprehended later.
Two women and a man sleeping on a pavement in Chennai were killed when a taxi ran them over at around midnight on Sunday.
The taxi driver is in custody. He told the police that he lost control of the car when he tried to avoid hitting a cow that had strayed on to the road. The car, the police said, swerved on to the pavement running over the three people.
Among those killed was a 28-year-old pregnant woman and her husband. All three are believed to have been rag-pickers in the area, the police said.
The taxi driver reportedly fled and was apprehended later. The Chennai traffic police said they are trying to determine if he was drunk or speeding.