We are the owners of a office building situate at Mumbai, Village Bandra, Taluka Andheri. Our Plot is a TP( Town Planning) plot. The Built up area of the building was approx. 6000 sq.ft. We were paying NA Tax of around 11,000/- Rupees per annum. In the year 2009 we demolished the existing structure and used TDR(Transfer of Development Rights) and constructed a new office building having built up area of approx. 12,000sq.feet. Now our building is ready and we are in the process of applying for an Occupation Certificate. We are informed that we were required to obtain NA( Non Agricultural) permission before we demolished our existing structure. We have applied for the permission now. We want to know as to how the NA Tax will be calculated . We are currently paying the same 11000/- what we used to pay before we demolished the building.We also want to know whether there is any penalty going to be charged and if so, at what rate. Kindly let us know, as we are being given several calculations by different people.