Floor space index

 The floor space index, also known as the floor area ratio (FAR), is the maximum area that can be constructed on a plot of land. 

It is regulated by the municipal or local authorities of the respective State government. 

FSI norms are usually set based on the National Building Code.

 It is calculated by dividing the total covered built-up area on all floors of a building by the area of the plot it stands on. For instance, if you have 1,000 square feet of land on which you want to build a residential or commercial building and the FSI in your locality is 1.5, then you could build up to 1,500 sq. ft of covered structures on the plot.