No legal permissions are required in this case. It is completely legal in India to install CCTV camera in office premises provided there are no hidden cameras or cameras installed in restroom.Otherwise it is completely ok to install camera in office as per legal prospective.
Departments working under Indian government for surveillance
Recently, many departments and agencies have been established, under government of India, in order to do surveillance in cyberspace (where online communication takes place between computers or networks), on personal messages, emails, cell phones or on social medias. Being fastest developing country, India has to make strong policies and regulations in order to protect IT industry as well as to protect privacy of every citizen.
The governmental bodies such as National Intelligence Grid, Central Monitoring System etc. have been setup for surveillance on internet, cell phones, private messages, as well as social media sites. But at this point of time, the protection of bodies itself i.e. powers and functions of authorities, situations under which surveillance can be done etc. and security of data to be kept by them is unknown. Also the provisions under which they have established are a question. It is possible that the data kept by these bodies can be misused by any private entity for any political or terrorist purpose which can endanger public privacy and safety at large.
Reference: Information Technology Act, 2000.