STEP-1 The limit of discharge of gases, vapour, or particulate matter from automobiles and various industries is referred to as an emission standard.Uncontrolled discharge of such polluting elements into air increase environmental pollution decreases air quality.STEP 2 Toxic emissions from businesses and vehicles cause severe air pollution.Various gases like carbon monoxide, carbon dioxide, sulfur dioxide, sulfur trioxide, nitrogen dioxide, particulate matters etc.To prevent environmental contamination produced by such emissions, a discharge limit must be established, as well as suitable safety precautions to eliminate various health risks.Emission Standard is the permissible limit of maximum rate or concentration of a particular polluting element that may be emitted or released from a particular source at a particular span of time.As a result of such emissions, severe environmental contamination and a variety of health risks emerge.