Comptroller and Auditor General is considered as Guardian of public purse and carries a range of important duties and functions. Various functions performed by the CAG as per provisions of constitution are:

• Role as Auditor General: The CAG is the head of Indian Audit and Accounts Department. Hence, auditing is one of the most significant functions of CAG to ensure accountability of executive at both Union and State level. Following types of audits are performed by CAG:

Financial Audit Functions of  Comptroller and Auditor General

• The CAG examines the accounts associated with all spending from the Consolidated Fund of India, as well as those from the Consolidated Funds of every State and Union Territory that has a legislative assembly. 
• The CAG also reviews all expenditures from the Contingency Fund of India and the Public Accounts of India, along with the Contingency Funds and Public Accounts of each State. 
• Moreover, the CAG audits trading, manufacturing, profit and loss statements, balance sheets, and other subsidiary accounts maintained by any Central or State government department. 
• The CAG audits all transactions of the Central and State government related to debt, deposits, advances and remittances business.
• Additionally, the CAG is responsible for auditing the finances of government-owned companies and other corporate entities when mandated by law. 
• He also conducts audits at the request of the President or Governor for any other authority. E.g., Audit of local bodies.

Role of CAG in Compliance Audits

• Furthermore, the CAG reviews the receipts and expenditures of both the Centre and the States to ensure that the established rules and procedures are aimed at providing an effective check on the assessment, collection, and proper allocation of revenues.

Propriety Audit by CAG

• Besides legal and regulatory audits, the CAG has the authority to perform propriety audits, which enable him to assess the wisdom, fidelity, and cost-effectiveness of government spending, thereby commenting on any wastefulness or extravagance observed. 
• A recent illustration of a propriety audit included the CAG’s report on mission mode projects of DRDO, where issues related to project completion delays and cost overruns were brought to attention. Conducting propriety audits falls under the discretionary power of the CAG. 

• Assistance to Union and States: Apart from auditing, CAG also provides assistance to Union and state governments in preparation of their annual financial statements and in any other related matters.
• Advisory role of CAG: The CAG plays an advisory role by informing the President on how the accounts of both the Centre and the States should be formatted and maintained.
• Compilation of accounts: CAG compiles and maintains the accounts of state governments. In 1976, the CAG was relieved from the duty of maintaining and compiling accounts for the Central Government due to the separation of duties between accounts and audit functions. The Controller General of Accounts under the Department of Expenditure, Ministry of Finance has the responsibility to compile and maintain the accounts of the central government.
• Reports of CAG: According to Article 151, the CAG’s reports on the Union’s accounts are submitted to the President, who presents them to Parliament. Similarly, the reports related to accounts of the State are submitted to the respective Governors and such reports are then caused to be laid before the respective state legislature by the Governor.
• Function related to Public Account Committee (PAC): In relation to the Public Accounts Committee (PAC), the CAG is regarded as the “friend, philosopher, and guide.” The PAC reviews the CAG’s reports, such as the Audit report on Appropriation accounts, Finance accounts, and Public Sector Undertakings, and conveys its findings to Parliament.

How CAG of India is different from CAG of Britain?

Provisions Ensuring the Independence of the Comptroller and Auditor General

To hold executive responsible and accountable for its financial policies, following provisions were incorporated in Constitution to ensure independence of CAG:

• Security of tenure: The CAG can only be removed following the same procedures and grounds that apply to a Supreme Court judge. This security in position is crucial for the CAG to execute his duties with impartiality.
• Expenses charged on Consolidated fund of India: All expenses related to the CAG, including salaries, are charged to the Consolidated Fund of India and do not require parliamentary approval. 
• No variation in salary and service conditions: The salary and other employment conditions of the CAG are established by Parliament, and these aspects (including salary, pension, or retirement age) cannot be reduced to the detriment of the CAG after their appointment. 

No reappointment: The CAG is not eligible for reappointment, and he/she cannot hold any governmental office, whether at the Central level or in any State, following retirement.