Simplify the following text for a Grade 13 native English-speaking person.
Original: Population : It is the economic and cultural center of the vast Volga-Vyatka economic region , and also the administrative center of Nizhny Novgorod Oblast and Volga Federal District .
Simplified: It is the economic and cultural center of the vast Volga-Vyatka economic region , and also the administrative center of Nizhny Novgorod Oblast and Volga Federal District .