As part of a massive drive to demolish illegal and risky buildings, Barishal City Corporation started knocking down the unauthorised portions of a multi-storey building in the city's Line Road area yesterday.

A BCC team comprised of an authorised officer, a building inspector and 40 labourers are enforcing the drive, authorities said.

The owner got approval to construct a nine-storey building, but he extended the dwelling to 11-storey, said Md Shakil, estate officer of BCC, who is leading the drive.

"So, BCC is demolishing the additional floors of the building," he said.

"We notified him [the building owner) before carrying out the drive, but he did not take any steps," he added.

Building owner Altaf Hossain, however, said he was not notified. "We submitted necessary documents to the BCC to extend the building to 11 storeys."

Shakil acknowledged of the application, but said Altaf was yet to get the approval.

BCC Superintendent Engineer Md Anisuzzaman said the city has more than 50,000 structures in total. Of them, over 5,000 are multi-storey, he said.

BCC has been conducting a survey to find out illegal and risky buildings for one month and is taking actions accordingly, said the official. "We will notify the building owners before drives. If they do not demolish the structures on their own, we will do so," he added.

BCC estate department sources said it has already found 34 buildings in bad shape. Once the survey is finished, the number will increase, they added.