First thing first, do not ever feed your cat whiska or any supermarket brand cat food, those food are hard to digest, and they have a lot more wastage than premium brand.
I don't know what kind of cat food you have in India, but you will do good with some above the quality brand (like iams) and also some super brand like royal canin and hills. If you cannot premium brand, I would suggest you go gourmet instead of feeding them supermarket food. I had two cat that caught FLUTDS by eating whiska and one cat got IBS from eating Friskie (another supermarket brand) I have had cat that actually died from eating cheap cat food...and been told supermarket brand cat food have heavy calcium which build up crystal in their urine and it also damage your cat's kidney.
Also, if you feed your cat cat food, it's important to have it mixed with dry and wet food together instead of just one. Usually doing dry and wet will get your cat more balance diet and will not caught diabetes that easy.
However, if you are on a budget and cannot afford premium cat food, then you can always go gourmet.
Find out what your cat like to eat (Fish, Chicket, Pork, Beef), once you know what your cat will eat, say your cat like fish, then you go get a raw fish, steam it to half to almost done (So you left the juice in) and then you serve them with rice (not a lot) and some veggie, it's fineifyour cat don't like rice and veggie, butif that do, you will need to get wet food that have veggin in it and mix it with the gourmet meat you made.
If you have money, I strongly recommend either Hills or Royal Canin.
For me, I feed my cat a brand called Optimum Cat food (the most expensive food in supermarket, but they have less calcium) and Innova Cat food (premium brand), Some time I do cook them gourmet meal and treat them with Hills Balance Diet brand wet food. My cats love them