Delhi arrests three contractors after a collapse officials link to supports pulled from wet concrete

The three, residents of the Ajmeri Gate area, were picked up in Sirohi village in Haryana's Faridabad district, police said. They are held under Section 105 of India's criminal code, the Bharatiya Nyaya Sanhita, which covers culpable homicide not amounting to murder, ANI and ThePrint reported. The case also names the building owner. These are police allegations that no court has tested. Two laborers, aged 40 and 45, died; reports put the injured at four or five. Rescuers cleared much of the debris by hand because the building sits at the end of a lane about three feet wide.

Sub-Divisional Magistrate Manoj Kumar said the centring, the temporary support under the slab, seems to have been removed while the concrete was still wet. The Municipal Corporation of Delhi's incident report, quoted by ThePrint, says shuttering under the third-floor lintel was taken out in a hurry, reportedly out of fear the work would be stopped, and that this slab's failure brought down the whole building. Deputy Commissioner of Police Rohit Rajbir Singh described a different sequence: the building fell while concrete was being poured for the third-floor slab. Residents said the floors came down in stages over about half an hour.

No building plan had been submitted for approval, according to the MCD. On April 28 it warned the owner that the building was in poor condition and told him to strengthen it under a structural engineer. Police flagged unauthorized work in June, but an inspection found what looked like repairs. The MCD now says the second and third floors were new construction passed off as repair work.

India's concrete code, IS 456:2000, sets minimum stripping times for ordinary Portland cement in normal weather. Slab soffit forms may come off after three days only if props go straight back in, and the props stay seven days for spans up to 4.5 m (about 15 feet) and 14 days beyond that. Above the table sits a strength rule: forms stay until the concrete can carry twice the stress it will see when they are struck.