Rohit Yadav, 24, got burn injuries on his nape, back, chest and left shoulder during the acid attack in Godamau village under jurisdiction of Morawan police station.
Police took him to an area hospital, from where he was shifted to Lucknow for further treatment.
Morawan police station officer Rajendra Rajawat said: "Prima facie, it is a case of one-sided love as the woman was not reciprocating his overtures. The man was reportedly stalking her."
The officer said that the man had not yet lodged a complaint, adding that the woman would be arrested if he lodged a complaint.
According to reports, Rohit was attacked at a dairy where he works as a cleaner. The woman was, apparently, hiding in the dairy since morning and threw acid as soon as Rohit entered the premises.
More than 40 cases of acid attacks, mostly on women, have been reported in Uttar Pradesh in 2018, according to the National Crime Records Bureau (NRCB) report released in January.
The Lucknow bench of Allahabad High Court had, earlier this month, sought a reply from the central and state governments on a plea pertaining to compliance of the directions issued by the Supreme Court to regulate the sale and distribution of acid.
The case is listed for hearing on January 31.
( With inputs from IANS )