(N/A) To control or reduce photochemical smog,the most direct method is to prevent the release of nitrogen oxides and hydrocarbons into the atmosphere. Methods include: $(i)$ Using high-quality catalytic converters in vehicles to convert harmful gases into harmless ones. $(ii)$ Using specific compounds that react with free radicals to prevent the formation of toxic smog components. $(iii)$ Planting trees like $Pinus$,$Juniperus$,$Pyrus$,and $Vitis$ that can metabolize nitrogen oxides.
$(b)$ Chlorinated solvents used in dry cleaning are carcinogenic. Replacing them with liquid $CO_2$ is a greener alternative. For bleaching,$H_2O_2$ is used instead of chlorine-based agents as it is effective and environmentally safe.
$(c)$ To reduce synthetic detergents,use soaps made from vegetable oils,which are biodegradable,unlike synthetic detergents.
$(d)$ Replace petrol and diesel with cleaner fuels like $CNG$,$LNG$,or hydrogen,which produce significantly less pollution.