The tyres are too wide for your car. I have the same profile on my car. There isn't any issue with the front tyres, but the rear ones ONLY touch the body when one is going at a pretty reasonable speed and the car goes over and un-leveled smooth road; that too when the level is changed abruptly. Bumps have not effect on it.
Your car must be facing the same issue. 13 isn't suitable for the suspension of Alto but if you put a tyre with thinner profile, you'll get over the issue you are facing at the moment.