According to police, the injured policeman, Shankar Singh (32), had reached the spot along with Sub-Inspector Satveer after receiving a call about a quarrel.
At around 1.30 A.M., when the duo reached the spot, they found one Lalit Kumar, a Grade IV employee of North Delhi Power Ltd (NDPL), beating his wife.
"As the duo tried to intervene, Kumar stabbed Singh in his neck... He was taken to a nearby hospital where his condition is stated to be out of danger," police said, adding that Kumar had been arrested and booked on attempt to murder charges.