Water is also polluted by the discharge of commercial and industrial waste. Sewage in drinking water is another (7)______ of water pollution as it contains germs and viruses.

There are three main (1) ______ of pollution: air pollution, water pollution and noise pollution.

(8)________  light at night can harm our eyes and also harm the hormones that help us to see things properly.

Eye strain, (7)______  of vision and stress are what people may get from light pollution.

Millions of tons of oil and coal (6)_______  to produce the power to light the sky.

Nowadays, cities are covered with lights from buildings, streets, advertising displays, many of which direct the lights up into the sky and into many unwanted places. The real problem is that it is very (5) _______ to apply light to almost everything at night.

In the past, we could sit out at night and (4) _____ at glittering stars in the sky and light from objects in the outer space.

Moreover, it is the type of pollution that (3) _____ more in cities than in rural areas.