Input required on Basement parking

For plot sizes such as your site, it is not advisable to go for basement parking.  For parking cars in basement,  a lot of area would get wasted in building a ramp. Once the car gets down to the basement, the car would have to leave way for more vehicles to be parked in that area. A normal car itself has size of 6 feet by 12 to 14 feet so it would not work in the dimensions provided.  You can try to build stilt parking, which is a parking on ground floor itself with a low height roof.