Sales tax is the most important source of revenue for the states due to several reasons.

1. Contribution to State Revenue:
Sales tax is a significant contributor to the revenue of the states. It is a form of indirect tax imposed on the sale of goods and services within a state. It is levied by the state government and collected by businesses on behalf of the government. The revenue generated from sales tax plays a crucial role in financing essential services and developmental activities carried out by the state.

2. Broad-based Tax:
Sales tax is a broad-based tax as it is imposed on a wide range of goods and services. It is applicable to various sectors such as manufacturing, retail, hospitality, telecommunications, and more. This wide coverage ensures that a large portion of the economic activities within the state is subject to taxation, leading to a significant revenue inflow.

3. Consumption-based Tax:
Sales tax is a consumption-based tax, meaning it is levied on the final consumption of goods and services. The tax burden falls on the end consumer, who ultimately pays the tax while purchasing the goods or services. As consumption is an essential part of any economy, sales tax revenue remains relatively stable even during economic fluctuations.

4. Flexibility and Autonomy:
States have the flexibility to determine the rate of sales tax based on their specific requirements. They can adjust the tax rates to generate higher revenue during times of economic growth or lower them to stimulate consumption during a recession. This autonomy allows states to tailor their tax policies according to their fiscal needs and economic conditions.

5. Ease of Administration:
Sales tax is relatively easier to administer compared to other forms of taxes. Businesses act as intermediaries in collecting and remitting the tax to the government. The government can rely on the existing infrastructure of businesses to collect tax efficiently. Moreover, technological advancements have made tax administration more streamlined and transparent, reducing the scope for tax evasion and improving compliance.

6. Less Burden on the Common Man:
Sales tax is spread across the population as it is paid by consumers while purchasing goods and services. It is an indirect tax, unlike direct taxes such as income tax, which are levied on individuals based on their income levels. This distribution of the tax burden reduces the direct impact on the common man and makes it a more acceptable form of taxation.

In conclusion, sales tax is the most important source of revenue for the states due to its broad-based nature, consumption-based approach, ease of administration, flexibility, and contribution to the state's finances. It provides a stable and significant revenue stream, allowing states to fund essential services, infrastructure development, and welfare programs.