Occupancy certificate

I have booked a residential flat in Bhiwandi taluka, in Thane District in the year 2015. The project falls under grampanchayat area and has got a commencement certificate from the collector office. The builder has got the RERA registration for the project. The project is having multiple buildings and is still under construction. The builder is likely to give possession very soon. However, as all the buildings are not ready and other development work is pending, he will be giving possession for completed building only. In this regard, i would request you to inform me : Who is the competent authority to issue a OCCUPANCY CERTIFICATE for projects in Bhiwandi taluka in Thane District ? Does builder is required to upload occupancy certificate from Grampanchayat on MAHARERA website? Can grampanchayat issue a OCCUPANCY CERTIFICATE for Thane Collector approved projects ? Can builder hand over possession without completing other development work like swimming pool, jogging track etc. ? Can builder give possession for few buildings when other other buildings are under construction?