Police said they were called just before 8pm (1900 GMT) to the Stratford Centre, close to London's Olympic Stadium, following reports of a group of males spraying what was believed to be a noxious substance.
London Ambulance Service tweeted that they had treated at least five patients after sending paramedics and a fleet of ambulances.
The injuries were believed to have been sustained in different locations, with one male arrested on suspicion of grievous bodily harm, police said.
Witnesses told the Press Association that an argument had broken out shortly beforehand.
There were 431 acid attacks in London last year, 398 of which were carried out in Stratford's borough of Newham.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)
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