The father of the 17-year-old acid attack victim says he has no clue who could have done such a thing and insists his daughter never complained about any harassment.

Minutes after she left her west Delhi home to go to school with her sister, the girl was attacked with acid by two masked bike-borne men.

Her sister rushed back home to inform her parents about the incident, while some shopkeepers helped her wash off the acid with milk.

Waiting outside the burns ward of Safdarjung Hospital where she is undergoing treatment, her father told reporters that her sister was with her at the time and they both were going to school.

"My daughter left home at 7.30 am. As soon as she crossed the street, she was attacked. The incident happened within six to seven minutes of her leaving the house. My youngest daughter had gone along with her and then came running to us," he told reporters here.

Asked whether she was being harassed or stalked, he said she never had any such complaint.

"She told me that they came and threw the acid and she could not see them. Doctors are examining her. If I had known about any such thing (harassment), I would have taken care and dropped her to school," he said.

A doctor at the hospital said that the girl has suffered seven to eight per cent facial burns and her eyes have also been affected.

The victim's father deals in rubber stamps and is also a property dealer, while her mother is a homemaker. She is the eldest among three siblings, that include a 12-year-old sister and a seven-year-old brother.

Recalling the morning trauma, the girl's mother said her younger daughter came running to her and asked for her father.

"She could not explain and started crying, and asked her father to rush with her," she said.

The girl’s uncle said the girl and her sister would walk to the Dwarka Mor Metro Station every morning. On Wednesday morning, the sisters were waiting for a friend to accompany them when the horror struck, he said.

"Suddenly, two men on motorcycle came there and threw acid on her. She rushed towards nearby shops for help. One of the shopkeepers even poured some milk on her face. She was screaming for help and asked her younger sister to call their father," he said.

After her younger sister rushed home and narrated the incident, their father rushed his daughter to a nearby hospital, from where she was referred to Deen Dayal Upadhyay Hospital and subsequently to the centre-run Safdarjung Hospital.

He learnt about the incident from his younger daughter. His wife too called him to tell him that she needed to go to the hospital, the uncle said.

"Her parents have not eaten anything since morning. We never knew about any incident of harassment earlier. If there was anything, she would have definitely shared it with her father. He is very frank and she is very close to him," he added.

As outrage spread over the acid attack, women's groups and others, including Lt Governor V K Saxena, raised questions on the availability of acid in markets despite a ban and Delhi Chief Minister Arvind Kejriwal asked how the accused could have gathered so much courage.