The Comptroller and Auditor General of India (CAG) is an authority, instituted by article 148 of the Constitution of India, which examines all invoices and expenditure of the Government of India and also the state governments. The Constitution of India caters for an independent office of the Comptroller and Auditor General of India (CAG). He is the leader of the Indian Audit as well as the Accounts Department. He is the guardian of the general public purse as well as regulates the whole monetary system of the country at both the levels- the center and State. He must promote the Constitution of India and the laws of Parliament in the area of monetary management
All the Union and State federal government divisions undergo the Audit of the CAG, including business and non-commercial federal government institutions, autonomous bodies funded from Union or State revenues and also firms where equity involvement by the government is upwards of 51%. These audits are evaluated by the Public Accounts Committees of the Parliament of India and State legislative bodies. The CAG also manages the Indian Audit and Accounts Service. The CAG is appointed by the President of India. CAG can be removed by the President only in accordance with the procedure mentioned in the Constitution that is the manner same as removal of a Supreme Court Judge.
The Comptroller and Auditor General will be responsible for putting together the accounts of the Union and also of each State from the initial and subsidiary accounts rendered to the Audit and accounts offices under his control by treasuries, offices or departments responsible for the keeping of such reports; and also for maintaining such accounts in relation to any one of the matters specified over. CAG aids the parliament/state legislatures to hold their corresponding governments liable. He is one of the defenses of the autonomous system of government in India, the others being the High court, the Election Commission of India, and the UPSC. It is for these factors Dr. B R Ambedkar claimed that the CAG should be the most crucial Officer under the Constitution of India and his responsibilities are even more critical than the duties of even the judiciary.