The child was allegedly raped by the husband of the owner of the school on Monday in west Delhi's Sagarpur area, and the incident came to light two days later, police said.
After the incident, the victim got ill and her family members admitted her in a hospital where doctors informed them that she has been raped.
The accused was arrested on Thursday.
Women and Child Development Minister Kiran Walia, after review of the situation in a meeting of Delhi Commission for Protection of Child's Right (DCPCR), asked the DCPCR chairman to initiate action.
Ms Walia asked the police to invoke stringent provisions against the culprit and directed them to invoke Section 23 of Juvenile Justice Act on the land lady who was running the school.
She also directed Deen Dayal Upadhyay hospital to provide medical care to the victim and asked the child psychologist to submit reports regularly to DCPCR and Child Welfare Committee.
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