The student had returned on May 24 and was placed under institutional quarantine, he said.
"The person is asymptomatic and has been shifted from a quarantine facility to a COVID care centre. His test reports arrived on Wednesday night, Health Secretary P Parthiban said.
Earlier, on Sunday, a 30-year-old Delhi returnee was diagnosed with the disease, almost a month after Arunachal was declared COVID 19-free.
The northeast state's first patient, a 31-year-old man from Lohit district, was discharged from a hospital here on April 17 following his recovery. UPL RMS RMS