The civic body has issued notices to 17 rooftop bars and restaurants for violating a standard operating procedure (SOP) that mandates at least half of the terrace of each establishment remain open and free of structures.

The SOP, published in August last year, specifies that 50% of a terrace must remain unoccupied to ensure safe evacuation during emergencies. Sources in the Kolkata Municipal Corporation (KMC) said the establishments that received notices had encroached on the entire rooftop, occupying the whole terrace.

“We have issued them notices and asked them to comply with the SOP,” said an official.

If a terrace has half of it open, visitors will have a space to wait safely until the fire brigade arrives, a KMC source said.

“We have the option of shutting down the establishments if they fail to adhere to the SOP even after reminders,” the official said.

Notices were sent over the last fortnight, and a second round of inspections is planned to ensure compliance, the official added.

The 50% open space rule applies only to existing rooftop structures. No new rooftop construction will be permitted going forward.

According to the SOP, no construction is allowed on refuge areas or refuge floors. Terraces must leave road-facing portions accessible for evacuations, enabling the fire department’s hydraulic ladders to reach people during an emergency. Doors to terraces cannot remain locked and clear exit paths must be maintained.

“The hydraulic ladder may not get access to the back of a building. The ladder will be of no use if the front portion is encroached,” mayor Firhad Hakim said when the SOP was published last year.

KMC officials said notices will also be issued to other rooftop establishments found violating other aspects of the SOP. “We will issue notices to more establishments based on our inspection report,” a KMC official said on Friday.

The crackdown follows Hakim’s announcement on May 2 last year that Calcutta’s rooftop cafes, lounges, bars and restaurants would be shut down if safety norms were ignored. The announcement came a day after chief minister Mamata Banerjee visited the fire-ravaged Rituraj Hotel in central Calcutta, where 14 people died on April 29. She had urged the business community to follow fire safety norms or face government action.

Inspection teams, comprising KMC officials, police and fire brigade officers, checked compliance on several points: possession of an electrical safety certificate, deployment of a trained fire marshal, availability of water storage, display of evacuation plans and accessible, well-lit emergency exits.