Oavoid compromising your car's aerodynamic properties, you should avoid

to carry heavy load on the vehicle's outside

Explanation:

Aerodyanmic properties of a car refer to its interactions with moving air and the properties which govern smooth movement of the car through air. Aerodynamics of a car address the concerns like lowering noise emission, prevention of heavy load and avoiding the luggage dragging.

Now when there will be great load outside the car,the air will resist the movement of car more, so it will be difficult for the car to cut through the air. Moreover, when a car carries huge amount of load outside its body, the frictional force by aerodynamic drag increases greatly. This can badly effect the performance of high speed cars like sports cars but for other normal cars it poses less hazards.

Hope it helps!

answer; ////increased water pollution; ///////////////////////