Air pollution is not reduced by

• Air pollution is caused by the release of harmful oxides of nitrogen, sulphur and carbon from the vehicular exhausts and industrial emissions primarily.
• Using precipitators allow the removal of dust from these emissions. 
• Keeping the air clean by minimizing the combustion of fossil fuels, less use of vehicles, use of catalytic converters can help in reducing the pollution.
•  Reusing waste allows the minimal production of non-degradable waste.

Hence, option B is the correct answer.