A video of delivery worker after the alleged assault has gone viral.
A customer and his brother allegedly used casteist slurs, spat on and assaulted a Dalit man who had come to a house in Aashiyana locality of Lucknow to deliver a food order from the delivery service Zomato, police said on Monday. They told him that they could not accept food touched by a Dalit, according to the police complaint.
A video of the delivery worker, Vineet Kumar Rawat, hassled after the alleged assault has also gone viral.
The main accused Ajay Singh, however, has said that it was just an "argument", after which the delivery worker "threatened to fix me". The FIR named Ajay Singh, a resident of Sector H, Aashiyana, his brother, and at least 12 others.
In his complaint, Mr Rawat said that on Saturday night when he reached the delivery location, a person came out of the house and asked for his name. He then hurled casteist remarks and assaulted him, as did others with him, refusing to formally cancel the order after declining to take it, it is alleged.
Police also put out a video detailing the complaint on Twitter.
But Ajay Singh has said, "I am myself from OBC (Other Backward Classes) caste. The allegation is that we asked for the caste of the delivery boy... [But] the maid who cooks food at my home is from the same caste as the delivery boy... There was an argument, yes."
"The issue was that my brother gargled and spat water before speaking to the delivery boy, and some of it accidentally landed on his bike." He claimed the delivery worker used an abusive word: "We pushed each other and he fell to the ground. Then he threatened to fix me."
A news report about the incident in a Hindi newspaper led to the state's chief opposition Samajwadi Party criticising Uttar Pradesh's BJP government.
"After decades, incidents of caste-based violence and mistreatment of Dalits have increased in the state under the BJP rule. People belonging to the same caste as Chief Minister Yogi Adityanath have not only misbehaved with a Dalit, but also attacked his self-respect and rights," the party posted in a tweet, which was retweeted by party president and former chief minister Akhilesh Yadav.
Meanwhile, Lucknow Police Commissioner DK Thakur told PTI that the matter is being investigated.