Question

What kind of problem will we face if number of vehicles keep on increasing

Answer 1

Thank you for asking the question!
If number of vehicle will keep on increasing then the the air pollution, water pollution and sound pollution will increase. The increase in the  number vehicles means the there will be more emission of harmful gasses. The liberation of gasses will ultimately increase the carbon mono oxide in the air. Liberation of gasses from vehicles also contaminate the water.
Hope it helps.

Answer 2

if the number of vehicles keep on increasing it would lead to many problems like; increased traffic on the road, air pollution, noise pollution, accidents, etc.