1. The developer has provided me with No Objection Certificate which states that they don't have any objection over owners occupying the building. Can this No Objection certificate be termed as Occupancy Certificate.
This NOC cannot be termed as OC. The OC can be given only by competent authority and not by builder.
2.Also the developer says there is no need for completion certificate in Gram panchayat areas. Is this true. I know for sure that he has not complied with certain in house measurements as per approved plan. Is Boisar already a under Municipality limits.
The gram panchayat is not empowered to issue CC or OC. Since your area is falling within Municipal limits, the municipal authorities only can issue OC as per provisions of law in this regard.
3. I have already taken possession, will this prejudice legal course of action.
If you have taken possession insist on occupation certificate from builder who has to provide it by obtaining the same from authority competent to issue this.