Paragraph//Comprehension-2 Environment is defined as the sum total of physical and biological factors that directly influence the survival, growth ,development and reproduction of organisms.The additon of certain harmful wastes to air , water and soil by a natural source or due to certain human activitites to such a level of concentration which adversely effects the quality of environment is called environmental p[ollution and the undesirable material thus added to environment is called pollutant Photochemeical smog is the term used for the air [pollutants produced in the atmopsphere as a result of photochemical reactions .Classical smog or London smog is a combination of particulateed and gaseouir oxided of suphur present in the atomospher.CO_(2) is not considered as atmospheric polllutant but its increased concentrate leads to green house effect. Increased CO_(2) content in the atmosphee will lead to