Want to construct house on my Bastu land located in EKWMA area

Good Evening, Myself Satyendra from Kolkata. I want to build a house on my own land, which is Bastu in nature located in EAST KOLKATA WETLANDS (EKWMA) area. I went to gram panchyat office (Kheadah 2 no.) for the permission to build my house. They told me to bring NOC from EKWMA office, then they will issue permission to build the house. I went to EKWMA office asking for the NOC with my documents as proof. And I have shown them their notification dated on 31st March 2006, in which my land is listed under urban/rural settlement area as per their (EKWMA) record. But they denied to issue any NOC. I have met Chief Technical Officer of EKWMA also but she too denied to issue any NOC. My question.... Can I start construct of my house without their permission ? What should I do so that they don't demolish or send any kind of legal notice to me ? And mostly policemen comes in that area, asking for bribe if you don't have any permission to build the house. Kindly guide me.... Thanks & Best Regards Satyendra