Yes, buying a penthouse flat in Bangalore is legal, provided all legal and regulatory requirements are met. When purchasing a penthouse, it is crucial to ensure that the seller has a clear and marketable title to the property. This means verifying that the property is free from legal encumbrances and that the seller has the right to transfer ownership. Conducting a thorough title search and engaging a legal expert can help in confirming the legitimacy of the property title. Additionally, it is essential to check if the building has been constructed according to approved plans and that all necessary permissions and approvals from local municipal authorities, such as the Bruhat Bengaluru Mahanagara Palike (BBMP), are in place. These approvals include building permits, environmental clearances, and adherence to zoning regulations. Compliance with these regulations helps avoid future legal complications and ensures that the property adheres to city planning norms.