The Reserve Bank of India (RBI) is India's central bank of Country.

The Reserve Bank of India was established in 1935 with the provision of Reserve Bank of India Act, 1934.

It has 19 regional offices, most of them in state capitals and 9 Sub-offices.

Subsidiaries
Fully owned: Deposit Insurance and Credit Guarantee Corporation of India(DICGC), Bharatiya Reserve Bank Note Mudran Private Limited(BRBNMPL), National Housing Bank(NHB)

Departments
Consumer Education and Protection Department
Corporate Strategy and Budget Department
Department of Communication
Department of Cooperative Bank Regulation
Department of Corporate Services
Department of Economic and Policy Research
Department of Government and Bank Accounts
Department of Non-Banking Supervision
Department of Statistics and Information Management
Financial Inclusion and Development Department
Financial Markets Regulation Department
Financial Stability Unit
Foreign Exchange Department
Inspection Department
Internal Debt Management Department
Legal Department
Monetary Policy Department
Rajbhasha Department
Premises Department
Secretary's Department
Central Vigilance Cell
Risk Monitoring Department
Financial Markets Operation Department
International Department
Human Resource Management Department
Department of Cooperative Bank Supervision
Department of External Investments and Operations
Department of Currency Management
Department of Non-Banking Regulation
Department of Information Technology
Department of Payment and Settlement Systems
Department of Banking Regulation
Department of Banking Supervision

As you are looking to get information about duties of Reserve Bank of India, so I am providing list of all duties and functions of Reserve Bank of India:

Duties and Functions of Reserve Bank of India
Issue of Bank Notes:
Banker to Government:
Lender of Last Resort:
Controller of Credit:
Custodian of Cash Reserves of Commercial Banks:
Central Clearance and Accounts Settlement:
Custodian of Country’s Foreign Currency Reserves: