The following is from the Odisha datasheet at censusindia.gov.

Based on the above map, the population of the Capital area consisting of Puri, Cuttack and Khurda districts is about 6.5 million. My guess is that if one draws a radius of 70 kms around the Bhubaneswar Secretariate-Assembly area, then the population of that would be between 5 to 6 million.