A group of migrants heading home after the lockdown over coronavirus was hosed down with a chlorine solution in Bareilly, triggering criticism and then an admission from the local authorities that they went too far.
A state government official, however, argued that such spraying of people is permitted internationally. But the authorities did not follow the right procedure, he said.
A fire brigade official said the migrants were sprayed with a solution containing sodium hypochlorite. It is often used to keep swimming pools sanitised.
The incident, caught on video and shared on social media, took place at Bareilly's Satellite bus station on Sunday.
The clip showed several migrants squatting on the ground as men in protective suits hosed them down. Someone is heard telling people to shut their eyes as the spraying begins.
Several people in the group, which included women and children, complained of a burning sensation in the eyes.
Chief Fire Officer C M Sharma said spraying the group with sodium hypochlorite was necessary for "disinfecting".
He said there is a burning sensation for 'two or three seconds' in the eyes when it gets into them, 'but it doesn't harm them'.
As a row erupted over the incident, District Magistrate Nitish Kumar blamed it on 'overzealous' civic body personnel and said action is being taken against them.
Those affected were seen by the chief medical officer, he said.
Congress general secretary Priyanka Gandhi Vadra, Samajwadi Party president Akhilesh Yadav and Bahujan Samjaj Party chief Mayawati lashed out at the Yogi Adityanath government in Uttar Pradesh over the treatment of migrants, hit by the lockdown and now heading for their homes.
Priyanka Gandhi asked the UP government not to do something this 'inhuman'.
"The labourers have already suffered a lot. Don't make them bathe with chemicals like this. This will not protect them but will create more problems for their health," she tweeted in Hindi.
Akhilesh Yadav said the spraying of chemicals on migrants to sanitise them had raised questions.
He asked if the World Health Organisation had given any directions on this. "What arrangements were there for people to change out of wet clothes? What alternatives are being provided for the food that gets wet due to the spraying?" Yadav tweeted.
Mayawati called the Bareilly incident 'inhuman and brutal' and asked the government to act.
"It would have been better if the borders of the state were sealed and two or three special trains run for labourers so that they could reach home", she tweeted.
The district magistrate said teams from the municipal corporation and the fire brigade were asked to sanitise the bus in which the migrant workers had travelled, but they were overzealous.
"Orders have been issued to take action against those concerned," he tweeted.
In Lucknow, Additional Chief Secretary (Information) Awanish Awasthi said such measures are allowed internationally, but the eyes of those being hosed down are kept closed.
He suggested that the procedure followed was wrong and those responsible in the municipal corporation will face action.
Awasthi said when there is a high 'infection load' disinfection is needed.