The first - H2O - of the four flat complexes at Maradu came down at 11.17 am on Saturday.
The demolition was successful without affecting nearby structures.
There was slight delay, which authorities attributed to the surveillance by Navy helicopters. The first siren went off as scheduled. However, the second siren went off 8 minutes late.
The five-storey building came down seconds after the one-minute long third siren which came 4 minutes after the second one.
A major part of the explosives were stored in the ground floor and some on the top floors to ensure that the building came down at one go and settled to the ground without any waste spreading to areas nearby.
The explosion went with precision as expected. There was a lot of dust that spread to areas nearby.
The Supreme Court had ordered demolition of four flat complexes as they had violated Coastal Regulation Zone (CRZ) norms.