Why was the 1973 budget called the 'Black Budget'?

The Union Budget for 1973-1974 is referred to as the 'Black Budget' as India had a deficit of ₹550 crore. The Budget was presented by then Finance Minister Yashwantrao Chavan. Chavan in his Budget speech stated that a deficit of this order was inescapable due to the difficult situation caused by the drought and the resultant shortfall in food grains.