A portion of the 165-year-old Katra Neel Gateway in Old Delhi's Chandni Chowk area collapsed on Friday morning, according to members of the Resident Welfare Association.
No casualty was reported as shops in the area had not opened by then, they said.
The top part of the unprotected heritage structure, built in 1857, caved in at around 9.30 am.
Anil Pershad, vice president of the Resident Welfare Association (Katra Neel) told PTI that police and fire brigade have barricaded the area and no entry is allowed.
Pershad's ancestral house, "Chunnamal haveli", is located adjacent to the Katra Neel Gateway.
"As the shops in the Chandni Chowk market open around 11 am, no one was present at the spot when the incident happened," Pershad said.
According to the National Mission on Monuments and Antiques, the gateway having two bay arch openings is made of red sandstone and appears as a conventional form of structure that was popular in the later Mughal period.
Following the incident, Alishah Ali, heritage professional and assistant curator at the upcoming Dara Shikoh Library museum, called for regular checks of similar buildings in Old Delhi.
"This is another example of absence of the concept of 'Urban Heritage', its preservation and a system for regular checks of the cultural heritage health status. Constant construction activities are taking place in Old Delhi, there is a mall coming up in Delhi advertised in the name of proximity with 'heritage'," Ali said.
"In the last few years, we have witnessed dilapidation of multiple havelis, dome of Masjid Mubarak Begum and various sites of concern. An aware community intervention with government support is needed," she added.