When driving a petrol-powered car you should accelerate firmly at half-throttle and upshift gears at 2,500 rpm. If you are driving a modern diesel-powered car you can shift up earlier, at about 2,000 rpm.
It is important not to accelerate at more than half-throttle or to exceed 3,000 rpm. If you do, the catalytic converter can stop working properly. If this happens, the emission of substances hazardous to health and the environment, such as hydrocarbons and nitrogen oxides, increases.