Is E-Khata apartment safe to buy ?

Dear Advocates/Experts, I am looking for a flat in an apartment named “Baldota Serenity” which is located at Rayasandra village, Off Sarjapura road. The apartment comes under village limits and is having E-Khata. The builder has got all necessary approvals for construction from BDA and he says that he has got the possession permission for flats, but there is NO OC for the apartment since it does not come under BBMP limits. The builder also states that all major banks including SBI has approved loans for the flats and I have even noticed that many residents are already residing in that apartment. 1. Please suggest me, if it is safe to buy a flat in that apartment.? 2. Builder has built Swimming pool, gym and party-hall on the terrace which is not mentioned in the construction plan and there is NO approvals for them. Builder has stated that there is NO approvals required for utilities/amenities built on the terrace unless it is a pent-house. - Is this a fact? Should I go ahead to buy this.? Could you please suggest me.