Answer 1

 The water of river Ganga has been polluted by various human activities like bathing, washing of clothes, immersion of ashes of dead bodies and unburnt corpses in the river. The untreated sewage and industrial waste is also discarded in the river. Chemical effluents from the industries are also discharged in it. More than hundred towns and cities lie along its way, which discharge their waste in it. This has harmed the aquatic life of this river.