Four persons including a woman sustained injuries on Thursday after part of a three-storey building they were residing in collapsed under the impact of a demolition work in a south Delhi locality, police said.

Police said the incident took place at around 7.30 p.m when some demolition work by the MCD was being carried out in the back portion of the old three-storey building in Arjun Nagar of Safdarjung Enclave area.