During the recess, the Departmentally Related Standing Committees of Parliament examine the Demand for Grants submitted by various Ministries.  The Demand for Grants are detailed explanations of that Ministry's annual budget which form part of the total budget of the government.  These are examined in detail, and the committees can approve of the demands, or suggest changes.  The Demand for Grants are finally discussed and voted on by the Parliament after the recess.  (The post below lists the ministries whose Demand for Grants will be discussed in detail after the recess). The issue is - how effective is the institution of Parliament in examining the budget?  Though India specific information on this subject is hard to find, K. Barraclough and B. Dorotinsky have cited the World Bank - OECD Budget procedures Database to formulate a table on the legislature approving the budget presented by the executive ("The Role of the Legislature in the Budget Process: A Comparative Review", Legislative Oversight and Budgeting).  I reproduce the table below:

In Practice, does the legislature generally approve the budget as presented by the Executive? (in percent)
Answer All Countries OECD Countries Presidential democracies Parliamentary democracies
It generally approves the budget with no changes 34 33 14 41
Minor changes are made (affecting less than 3% of total spending) 63 67 71 59
Major changes are made (affecting more than 3% but less than 20% of total spending) 2 0 7 0
The budget approved is significantly different (affecting more than 20% of total spending) 0 0 0 0
Sources:  K. Barraclough and B. Dorotinsky; PRS.

The recent 2G-controversy and the related debate over the role of the PAC as opposed to the JPC also raises a broader Issue regarding the general scrutiny of government finances by Parliament.  Oversight of the government’s finances involves the scrutiny of the government’s financial proposals and policies.  The Indian Constitution vests this power with the Parliament by providing that (a) taxes cannot be imposed or collected without the authority of law, and (b) expenditure cannot be incurred without the authorisation of the legislature. The Indian Parliament exercises financial oversight over the government budget in two stages: (1) at the time of presentation of the annual budget, and (2) reviewing the government’s budget implementation efforts through the year. The Parliament scrutinises the annual budget (a) on the floor of the House, and (b) by the departmentally related standing committees. Scrutiny on the floor of the House The main scrutiny of the budget in the Lok Sabha takes place through: (a) General discussion and voting: The general discussion on the Budget is held on a day subsequent to the presentation of the Budget by the Finance Minister.  Discussion at this stage is confined to the general examination of the Budget and policies of taxation expressed during the budget speech. (b) Discussion on Demand for Grants: The general discussion is followed by a discussion on the Demand for Grants of different ministries. A certain number of days or hours are allocated for the discussion of all the demands. However, not all the demands are discussed within the allotted number of days. The remaining undiscussed demands are disposed of by the Speaker after the agreement of the House.  This process is known as the ‘Guillotine’.  Figure 1 shows the number of Demands discussed and guillotined over the last five years.  It shows that nearly 90% of the Demands are not discussed every year. Some Important Budget Documents Annual Financial Statement – Statement of the estimated receipts and expenditure of the government. Demand for Grants –Expenditure required to be voted by the Lok Sabha.  A separate Demand is required to be presented for each department of the government. Supplementary Demand for Grants – Presented when (a) authorized amounts are insufficient, or (b) need for additional expenditure has arisen. Finance Bill – Details the imposition of taxes, the rates of taxation, and its regulation. Detailed Demand for Grants – Prepared on the basis of the Demand for Grants.  These show further break-up of objects by expenditure, and also actual expenditure in the previous year. For more details see detailed note on Financial Oversight by Parliament here.