Enclosure of stilt parking

The facts posted are not clear.  Is the Flat owners association register or not?  Consult a local senior lawyer for guidance. 

It's independent flat. No association or society or committee. Normally we do meeting together and decide things. That's it.

Facts posted are  vague.

It is better to show relevant documents to a local prudent lawyer.

Enclosing a stilt parking space—even with a removable grill structure—involves a combination of municipal building rules under the Kolkata Municipal Corporation (KMC) and property laws under the West Bengal Apartment Ownership framework.

Under KMC Building Regulations and the West Bengal Municipal Building Rules, stilt parking areas are approved specifically for vehicle parking and maneuvering; Enclosing a stilt area to turn it into a room, storage, or commercial space without prior municipal approval is strictly prohibited. The Stilt levels are required to maintain open sides for natural light, ventilation, and fire safety compliance. Installing solid walls or heavy blockages violates the original sanctioned plan.

Any physical alteration or addition to the structural elements or open spaces of a sanctioned building plan requires KMC's Building Department approval or a clearance from a Licensed Building Architect (LBA).

Even when a specific parking bay is allotted for the exclusive use of a flat owner, the stilt floor as a whole (columns, driveways, ventilation passages) is classified as a common structural element. Without an official association board to issue an NOC, any single flat owner can object to the installation. If a neighbor complains to the KMC Building Department or local police claiming obstruction or alteration of common spaces, KMC is obligated to inspect.

Have an LBA review the original sanctioned plan of your building. They can confirm whether a light, collapsible grill frame triggers a formal amendment requirement with KMC.  Avoid any brickwork, asbestos, or solid sheeting that alters the open-air nature of the stilt floor.