A delivery driver "left fighting for his life" after an acid attack in east London could lose his sight.
The 32-year-old had a substance repeatedly thrown in his face by two men who tried to steal his moped in Walthamstow on Thursday at 18:00 GMT.
In a separate attack in Tottenham about 30 minutes later, another delivery driver, also 32, had a corrosive substance thrown at him.
A teenage boy has been arrested over the attack in Walthamstow.
He is being held on suspicion of committing grievous bodily harm and is in custody at an east London police station, the Met said.
BBC home affairs correspondent Danny Shaw said police "strongly suspect" both attacks are linked.
He added that the pizza delivery driver attacked on Walpole Street has injuries to his throat, face, oesophagus and eyes and is in an induced coma.
Detectives said the man was likely to lose sight in both eyes.
"This attack has left a man fighting for his life and with terrible eye injuries," Det Ch Insp Gordon Henderson said.
"This was an innocent man going about his work as a delivery driver, who may never see again."
In the second attack, two men approached the victim on Yarmouth Crescent, Tottenham, in a bid to steal his moped.
He was taken to hospital but his injuries are not thought to be life-threatening.
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