introduction of four-stroke engines which pollute less
ban on leaded petrol
proper monitoring of the streets so that vehicles which which polluted are identified and proper action taken again them by the authorities.
factories which are issuing pollutant gases should be fitted with proper purification units which minimize the harm that gases, if untreated, would do to the environment
vehicles should be fitted with catalytic converters, which take away some of the more harmful gases from the car exhaust and minimize acidic gases in the environment.