New Delhi, June 2 -- The six-storey building that collapsed in Saidulajab on Saturday was one of more than 125,000 properties that the Municipal Corporation of Delhi (MCD) has "booked" - a label the civic body slaps on structures found to have violated regulatory norms - but against which authorities have taken little or no action at all, HT has learnt. At least 125,755 properties in Delhi have been booked as of May 31 this year, showed MCD records, and these buildings and their owners are liable to face a raft of penalties, including a halt on further construction, a curb on future transactions and the potential for further action. But in November 2025, the Delhi government allowed power connections to these buildings to be restored - a key penalty for illegal constructions that was in place for decades. The government cited "public interest" grounds and pointed to long-drawn court cases. This comes even as it emerged that Delhi Police wrote to MCD in March about the plot and asked it to "verify whether the construction is per sanctioned plan or otherwise". Police flagged the construction of a fifth floor in the building, according to a letter that HT has seen. However, MCD took little action on the notice. That building collapsed on Saturday evening, falling onto a neighbouring canteen, killing six people and injuring nine. On Monday evening, police said they arrested the building's owner, Karamveer Zaildar, a 71-year-old resident of Church Road in Vasant Kunj, and booked him for culpable homicide not amounting to murder, negligent conduct with respect to buildings and causing hurt....