How did owner's plan to create more rental space lead to collapse of PG building in Delhi?

The deadly collapse of a fifty-year-old PG building in Delhi's Satya Niketan was caused by water accumulation in the basement, coupled with repair work on the ageing structure, confirmed Delhi CM Rekha Gupta. The PG owners were constructing more rental space in basement. During repairs, a pillar became unstable, weakening the structure and causing the building to collapse, killing six.