How to write a proper paragraph

Every paragraph in an essay contains a main idea, elaboration and examples. I will show you one typical paragraph. Look at the following example of a paragraph in an essay entitled 'Causes of Air Pollution'

One of factors of air pollution is open burning. When someone burns rubbish in the open air, the smoke from the burning litter will rise to the air causing the air to be polluted. For example, when we burn dried leaves or paper in the open space, the smoke containing minute particles will go up to the air forming pollutants there.

In the above paragraph, the topic sentence is open burning causes air pollution. It is elaborated by saying that smoke from open burning causes the air to be polluted. An example of open burning is then added, that is burning dried leaves or paper will produce smoke which brings about air pollution.

Try to write a simple paragraph like the one above as a practice.