NDMC had formed a six-member panel, comprising structural safety experts from IIT Delhi, Central Public Works Department, NDMC and the Sub Divisional Magistrate of the area to inspect the collapse sites and ascertain the reason behind the tragedy.
"We are conducting a safety audit as the collapses have raised questions over the structural stability of the structures in CP. Over 900 units have been identified as dangerous and will be issued notices to either modify the structures to fall in line with the safety norms or face action," a senior NDMC official said.
The civic body had last week sealed 21 rooftop restaurants and bars for flouting norms.
According to NDMC officials, terraces or balconies in heritage buildings cannot be used for any kind of commercial activity.
"The audit team has reported that the terraces were overburdened with the weight of generator sets, furniture, water tanks and other heavy equipment resulting in the crumbling of old buildings. Seepage, cracks in walls, and dilapidated plasters have also weakened the foundation of the buildings," he added.
The roof of a building in C-block, above Jain Book Store, collapsed on February 2, while another roof of a one-storey building housing a popular resto bar, The Unplugged Courtyard (UC) in L-block, collapsed on February 11.