The deceased has been identified as Daya Shankar, while the other two injured, identified as Deena and Deepak, were rushed to Baba Saheb Ambedkar Hospital for treatment, they said.
According to the fire department, a call was received around 5.40 pm regarding the incident.
Meanwhile, a Delhi Metro Rail Corporation spokesperson said Director-Works DMRC Jitender Tyagi has ordered an inquiry into the incident.
"An incident occurred near Sector 18 Rohini when an agency hired by a DMRC Contractor M/s J Kumar unauthorisedly began utility identification work for gas pipeline without necessary safety precautions as prescribed by DMRC," the spokesperson said.