VIII. Fill the blanks with the words given: harmful / polluted / garbage / serious / atmosphere / environment / increased / pollution Big cities in the world are facing (1)…………problems of (2)…………..pollution, especially air and water pollution. The great number of motorcycles is on of the main causes of air (3)……………. Smoke coming out from vehicles contains a big amount of lead which is very (4)……………….to health. Besides, factories in the cities release so much carbon dioxide into the (5)……………….every day. These factories pollute not only the air but also the water as well. Poisonous sewage from factories flows directly into rivers without any treatment . Moreover, tons of (6)……………..are thrown into rivers, turning them into huge garbage dumps.