P--------------- is the introduction of contaminants into the natural environment that cause adverse change.

A f---------- fuel is a fuel formed by natural processes, such as anaerobic decomposition of buried dead organisms

F------------ are strong, unpleasant, and sometimes dangerous gas or smoke like , for example, the ones released by cars.

The ozone l---------- is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet radiation.

Cutting down trees without restrictions brings about d-------------------

S--------------- energy is energy that we will never use up or deplete. It is inexhaustible, like , for example, the kind we get from wind, sun or water.

A h-------------- car is one that uses more than one means of propulsion - that means combining a petrol or diesel engine with an electric motor.

Using cloth bags instead of plastic ones is environmentally- f----------

It´s vital to use r--------------- energies like the solar one because they pollute less than the traditional sources of energy.

S------------ is air pollution that reduces visibility. It is a mixture of "smoke" and "fog".

A l-------------- site is a site for the disposal of waste materials.

C----------- ch------------ is the most evident effect of global warming: temperatures aare becoming more extreme all over the world.