The size of the annual budget is the amount the central government spends per year. The government lays out the estimated earnings and spending for the course of the year.

These estimates may undergo changes during the course of the year.

For instance, income tax collections may turn out to be higher or lower than expected. Similarly, expenditure may overshoot or fall short.

Gaurav Choudhury, Deputy Executive Editor at Moneycontrol explains everything you need to know about how revenue and spending estimates can change.