Lead (Pb), one of the important criteria air pollutants, was widely used in petrol due to its efficacy in

Lead was added to petrol as tetraethyl lead to prevent engine knock, acting as an antiknocking agent.

Knocking is the harmful pre-ignition that lead was meant to stop, not cause.

Lead does not serve as a catalytic converter and in fact poisons catalysts.

Lead was not added for lubrication.

Its value lay in raising the fuel's resistance to knocking.

Leaded petrol was phased out because lead is a toxic air pollutant.