The Uttar Pradesh police has suspended them and ordered an inquiry into the conduct of the policewomen, who had been tasked with protecting the woman at King George's Medical University.
Senior police officer A Satish Ganesh had termed the three constables "insensitive" and promised immediate action.
This morning, Chief Minister Yogi Adityanath visited the hospital and ordered the police to arrest the woman's attackers. The two accused were arrested hours later.
Just after the Chief Minister left, the constables started taking selfies next to the woman who has allegedly been attacked multiple times.
Gang-raped in 2008 by men in her village who also poured acid on her abdomen, the woman had allegedly asked for protection after repeated attacks.
Earlier this month, she had gone to Unchahar, around 100 km from Lucknow where she works at a cafe for acid attack survivors, for her teen daughter's exams. When she was returning by train yesterday, she was attacked.
When the train arrived in Lucknow, the woman went to the police and, unable to speak, wrote down what happened to her.
Yogi Adityanath's BJP swept the Uttar Pradesh election following a campaign that highlighted lawlessness and crimes against women on the previous Samajwadi Party's watch.