You can file RTI to BBMP. The Bruhat Bengaluru Mahanagara Palike, is the administrative body responsible for civic amenities and some infrastructural assets of the Greater Bangalore metropolitan area. The BBMP represents the third level of government (the Central Government and State Government being the first two levels). BBMP is run by a city council composed of elected representatives, called "corporators", one from each of the wards (localities) of the city. Hence it is a public authority under section 2 (h) and under section 2 (f), 2 (j) and section 6 we can ask for the certified copy of the sanction plan copy of any building. For building with g4+ floors the application must be made to the Town planning department north and Town planning department north of BBMP Head office and below g4 building application must be made to the town planning department of BBMP Zonal office.
For further assistance and to have a better understanding on filing RTI, you may visit the below mentioned link: