Why is pollution considered as a major problem in urban areas?

Concentrated energy use leads to greater air pollution with significant impact on human health. Automobile exhaust produces elevated lead levels in urban air. Large volumes of uncollected waste create multiple health hazards. Urban development can magnify the risk of environmental hazards such as flash flooding.

read the sentence below and answer the question that follows. one of the norms in the village was to meet at the town square on fridays for a community dinner and dance. the underlined word in the sentence above is best defined as a a. cultural element shared by all people around the world b. specific area in a town used for traditional community events c. religious custom accepted and practiced by all members of a village d. behavioral pattern that is regularly accepted by a group of people