India follows the old 'round pin' radial British system, in red and black PVC, still has a lot of class zero (metal case no earth, not double insulated)gear. Some of us are remarkably familiar with it.
The Indian wiring regs are based on BS7671 (like ireland, like Malta - its the old colonial influence what-ho)
now i've finished berating my colleagues, to the question,
If you know the live-earth fault resistance, which sets the prospective maximum fault current, and the type of load you can determine what you need.
Type a (instant trip) is never used, and isn't readily available in the UK
Type B, C D all have two mechanisms for tripping,
1) a thermal part which (like a fuse) does not fire for very brief overloads, but will trip before the cables get dangerously hot. This sets the rating of the trip, and the working load and cable size determine that.
2) a magnetic part, with a much higher tripping current, that operates near instantly. The secret is to allow normal cold filament, start motor type surges, without tripping the breaker, and yet still operate near instantly if the cable is cut or a dead-short is applied.
Most of the 230V world ( Russia, China and the EU) uses 16A radials with type C breakers (5 to 10X transient rating), we tend to use 32 A breaker with a type B (2 to 5 X transient rating) characteristic -the effect is the same, the surges for domestic equipment like TV or fridge are in the range 50-80A, but a 200A dead short fault guarantees instant tripping.
Opinion is divided over type B or C at 6A for separated lighting circuits, actually both protect the wire against overload, but B can be a bit too frisky on installations with many lamps switching together (a cold tungsten filament is about 1/12 the resistance of a hot one.)
Type D is normally reserved for heavy machines and is best decided only in consultation with the makers.
Hope that gets you started
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