<b>Complete the crossword puzzle with the help of clues given below:</b><br><b>Across</b><br><b>1.</b> Pollutant which was used in refrigerators and air conditioners. (18)<br><b>3.</b> Produced on incomplete combustion of fuels (14)<br><b>6.</b> This chemical protects our crops and is washed into water bodies from the field. (9)<br><b>Down</b><br><b>2.</b> This layer protects us from harmful ultraviolet rays. (5)<br><b>4.</b> It is essential for combustion. (6)<br><b>5.</b> Disease which is caused by drinking contaminated water. (7)<br><b>7.</b> River which is famous in India and sustains most of the northern, central and eastern Indian population. (5)<br><img src="/assets/questions/media/ncert-exemplar-class-8-science-chapter-18-solution.png">"