21-year-old Amit was injured in a fight with locals at Raja Vihar slum in Samaypur Badli on July 21 night.
The locals had beaten him with sticks, a friend said, adding that when he interfered, they beat him also. Police later arrived and lathi-charged them, resulting in grievous injuries to both of them, he said.
Amit was admitted to Ambedkar Hospital from where he was shifted to Saroj Hospital in Rohini where he died today, a police officer said.
A case of rioting was registered and police has arrested an accused and detained a juvenile. Investigation is on to identify and arrest other accused, he added.