What does the danger of deficit mean?

It should refer to the fiscal deficit crisis.

Deficit, mostly used in finance, means losing money. The difference between fiscal expenditure and income in a fiscal year. It is named because it is used to being expressed in red letters in accounting. In China, fiscal revenue and expenditure are balanced through the national budget, and fiscal deficit is usually manifested as the difference between expenditure and income in budget implementation, so it is also called budget deficit. A year's fiscal revenue represents a part of the social products that the country can control in that year. Fiscal expenditure is greater than income, resulting in a deficit, which means that the social purchasing power formed by this part of expenditure has no corresponding social products as material guarantee.