A teenager was taken to hospital with stab wounds and facial injuries - believed to have been caused by a noxious substance - after an incident in Lower Clapton.
Met Police officers are investigating the incident after being called to Rushmore Road at 3.13pm on January 30 to reports a male had been stabbed.
Emergency services attended and the 16-year-old boy was taken to an East London hospital by the London Ambulance Service, where he remains in a stable condition.
His injuries are not believed to be life-threatening and a crime scene remains in place.
A spokesperson for Scotland Yard said: "At this early stage, there have been no arrests."
Anyone with information is asked to call police via 101 quoting reference Cad 4350/30Jan.
Alternatively, call the independent charity Crimestoppers anonymously on 0800 555 111.
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