CAG is a constitutional body under article 148 that ensures Executive accountability in India. It audit the receipts and expenditures of the Central Government, State Governments, and other bodies that receive funding from the Government. B.R Ambedkar called CAG as most important office in Constitution of India.

Role of CAG ensuring legality of expenditure 

1. Article 149: CAG audits all receipts and expenditures of the Union and States to ensure legality. Eg: In the 2G Spectrum Case (2010), CAG found illegal allocation of licenses without proper procedures.
2. Article 266: Funds from the Consolidated Fund can only be withdrawn with legislative approval. Eg: CAG’s audit of Assam’s finances revealed unauthorized withdrawals from the Consolidated Fund.
3. Article 150: The accounts must be kept in a form prescribed by the President on CAG’s advice. Eg: CAG’s audit of Railway finances found non-compliance with the prescribed format.
4. Section 13 of CAG Act, 1971: Authorizes CAG to audit expenditures to ensure they are legally available for the purpose. Eg: CAG’s audit of MGNREGA funds revealed misuse on non-permitted projects.
5. Article 151: CAG submits audit reports to the President/Governor for presentation in Parliament/State Legislature. Eg: CAG’s report on Commonwealth Games highlighted legal breaches in procurement.

CAG ensuring propriety of expenditure 

1. Section 17 of CAG Act, 1971: Allows CAG to audit the efficiency and propriety of transactions.
   Eg: In the Coal Block Allocation audit, CAG questioned the lack of competitive bidding.
2. Regulation 41: CAG can conduct propriety audits to ensure spending is wise and economical. Eg: CAG’s audit of Mid-Day Meal Scheme found excessive infrastructure spending with little impact.
3. Propriety Audit: CAG examines the fairness and wisdom of expenditures. Eg: In the Debt Waiver Scheme audit, CAG found ineligible beneficiaries receiving waivers.
4. Subsidy/Grant Audits: CAG audits the effective use of government subsidies. Eg: In Ujjwala Yojana, CAG found that many beneficiaries could not afford LPG refills.
5. Transparency in Spending: Eg. audits of projects like the Delhi Metro Rail Corporation are published online, allowing citizens to scrutinize how public funds are utilized. 
6. Safeguarding Public Interest by scrutinizing financial management practices within government entities. Eg. CAG’s audits revealed inefficiencies and mismanagement in Air India.

Issues with CAG

1. Though legal and regulatory audits are compulsory, but proprietary audits are discretionary.                         
2. Paul Appleby criticized role of CAG as auditor by saying it has negative and paralyzing effect on administration.
3. Accounts are audited after actual expenditure is made, a mere post-facto audit.

Adopting a British System where CAG is both Comptroller as well as Auditor General can strengthen role of CAG as  one of the bulwarks of the democratic system of government in India.