India, June 13 -- A fire that killed three people in a residential building in Tughlakabad Extension on Friday has exposed a critical misunderstanding at the heart of Delhi's urban development expansion: that the regularisation of an unauthorised colony does not mean its buildings are structurally safe or compliant with construction norms.

Urban planning experts HT spoke to on Friday stressed that the tragedy highlights how parts of Delhi have been brought into the legal fold over the decades for the purposes of ownership rights, electricity, water connections and taxation, without a corresponding exercise to verify whether buildings meet basic safety standards.

Tughlakabad Extension, where the fire occurred, was regularised in 1987 und...