Does the petrol in the car freezes and become ice, since the temperature drops to - degrees.
Yes, petrol can solidify as any fluid can. Petrol solidifies around -50 degrees C.
Diesel freezes in stages. The first stage is the so-called cloudpoint, where the paraffines in the diesel start to solidify. When the temperature drops even further, then you reach the Cold Filter Plugging Point; that doesn't mean the diesel is frozen, but it means that at these temperatures, the filter might clog up by paraffine particles.
In the winter (from mid-October) companies in Europe sell so-called winter diesel. In this diesel they use less paraffines and more so-called "light" elements, but they also add so-called "flow improvers" to guarantee a certain viscosity.. This winter diesel is "protected" until -19 degrees C.
Hope this helps a little.