how to reduce budget deficit ?

The answer to your question is already covered in our study material. Follow the given link and scroll down to the topic ' Measures to correct budgetary deficits' to view the same.

https://www.meritnation.com/cbse/class12-commerce/studymaterial/economics/introductory-macroeconomics/the-government-budget-and-the-economy/341_1990_5851#slide3_measures-of-budget-deficit-and-fiscal-policy