Is income from immovable property taxable in India? If yes than what are the investments available to avoid.?

Me and wife are NRI for the lat 20 yrs. We had 2 flats in Goa which we had purchased out of NR remitances. We earned 11.5 lacs on the sale of these 2 flats. We want to purchse a flat in Mumbai may be after a year. Till that time we want to put this amount in a FD in the bank. Is this amount taxable? What are the other IT risks.