What are the environmental consequences of using fossil fuels? Suggest the steps to minimise

What are the environmental consequences of using fossil fuels? Suggest the steps to minimise the pollution caused by various sources of energy including non- conventional sources of energy causing global warming.

Steps to minimise the pollution are:
(i) The pollution caused by burning fossil fuels can be reduced by increasing the efficiency of the combustion process and using various techniques to produce the smokeless appliances.
(ii) The air pollution caused by burning of coal or petroleum products can be reduced by afforestation.
(iii) The planned and judicious use of energy can minimise the pollution, e.g. use of Liquid Petroleum Gas (LPG) as domestic fuel and Compressed Natural Gas (CNG) in transportation vehicles.