The comptroller and the auditor general of India is considered as the person responsible for the purse of India. This means that all official payments need to go by him on order to be approved and assigned. Without his approval, the purse cannot be accessed or used. The general was given this authority under the article 148 in the constitution of India.
The auditor gets all the receipts and handles all payments that fall under the government of India and the state government. It also includes all bodies and authorities that are financed by the government as well. This means that a major part of the country look up to the auditor general for payment approval.
CAG is an authority established by the Constitution of India under Article 148, who audits all receipts and expenditure of the Government of India and the Stae Government, including those of the bodies and authorities substantially financed by the Governemnt.