Please find the information on at least 3-4 polluted cities .
--Preventive measures can be common.
--Causes may differ..if same write together.
--make use of maps , diagrams, pictures etc.
Contemporary learning is blog created mainly for the benefit of students to provide them with more and extra in socialsciences.It would give them an easy access to the work done in classroom and also a record of what they have missed out on.