Indian wiring practice, as set out in IS 732 and the National Building Code, limits a lighting sub-circuit to ten points of lights, fans and 6 A socket outlets, with the total connected load on that circuit held to 800 W. Power sub-circuits are treated separately: each carries at most two 16 A socket outlets with a limit of 3000 W. The rule exists so that one MCB protects a load it can actually clear, and so that a single fault does not put a whole floor in the dark.
In a typical 2 BHK flat that works out to one lighting circuit per one or two rooms and a dedicated power circuit for every air conditioner, geyser and kitchen. Each lighting circuit is normally wired in 1.5 sq mm and each power circuit in 2.5 or 4 sq mm; Anushakti HR FR LSH covers both. The distribution board wiring guide shows how the circuits are grouped at the DB.