In USA, various devices such as the positive crankcase ventilation valve and catalytic converter have been developed to reduce exhaust emissions by automobiles, but these devices are not always fully maintained by the public.
Likewise, particulate pollution from industry and power generation can be controlled by electrostatic precipitators which are capable of dramatically reducing smoke and dust. Gaseous pollutants of industry and power station can be removed by chemical means, i.e., differential solubility of gases in water.
A fine spray of water in a device known as a “scrubber” can effectively separate many gases such as ammonia and sulphur dioxide. Other gases may be removed by filtration or absorption through activated carbon, and still others by chemical conversion to inert or innocuous materials.
In India, air pollution control legislation envisages the formation of air pollution boards at the Central and State levels “with powers to issue and revoke licenses to polluting industries, enforce emission standards and frame rules and regulations for the control of air pollution”.
The legislation is primarily directed the highly polluting industries such as iron and steel, textiles and power plants. The Board will have power to prohibit certain trades and manufacturing processes in notified areas and prescribes emission standards in scheduled premises.
The legislation is also understood to ban the burning of garbage and other waste products in urban areas as well as the fouling up of air by burning smoking fuels for domestic purposes. Recently, Bombay Smoke Nuisance Act has been enforced only in case of smoke emanating from the chimneys of industrial units.
However, there is a need of legislation to deal with fumes of petro-chemical units, ash, carbon particles; unpalatable smell and even noise from industrial units (see Gopal Bhargava, in the Hindustan Times Magzine, pp. 1, 9th April, 1978).