The quality of coal found in Arunachal Pradesh is generally:

High-grade
Medium-grade
Low-grade
Extremely poor quality

The quality of coal found in Arunachal Pradesh is generally low-grade. This means that it has a high ash content and a low calorific value. As a result, it is not suitable for use in power plants or other industrial applications. However, it can be used for low-grade purposes such as brick making and road construction.

The quality of coal is determined by its grade, which is a measure of its carbon content. The higher the carbon content, the higher the grade of the coal. Coal with a high carbon content burns more cleanly and produces more heat than coal with a low carbon content.

The ash content of coal is a measure of the amount of non-combustible material in the coal. The higher the ash content, the lower the quality of the coal. Coal with a high ash content produces more ash when it burns, which can be a problem for power plants and other industrial applications.

The calorific value of coal is a measure of the amount of heat that can be produced by burning a unit of coal. The higher the calorific value, the higher the quality of the coal. Coal with a high calorific value is more efficient to burn and produces more heat than coal with a low calorific value.

The quality of coal found in Arunachal Pradesh is generally low-grade. This means that it has a high ash content and a low calorific value. As a result, it is not suitable for use in power plants or other industrial applications. However, it can be used for low-grade purposes such as brick making and road construction.