Since 1996, the importance of green chemistry (GC) increased, thanks to 10 principles that require minimizing of waste, of hazardous solvents and quantity of solvents, energy consumption etc. GC was born due to increase in pollution with the aim of safeguarding the environment and the operator. Thus, years later green analytical chemistry (GAC) was born, sectoring GC principles in analytical field. In addition, GAC had, and still has, a big impact on daily work. For this reason index that “quantify” the greenness of a procedure were born and someone most used are explicated in this chapter. Chapter starts with a general view on green and GAC trends, following with an in-depth analysis of them, principle by principle, there is also a scale of solvents, which can be helpful for scientist to choice the right one. Later, GAC principles are analyzed and there are some examples of most used index, with a focus on their growth and specificity, and this part can be helpful to understand how to read a GAC index.
