Unit 1: how good is legislation at reducing negative externalities?

You decide

http://www.bbc.co.uk/news/uk-england-birmingham-16682596

a) What is the negative externality in the clip?
b) Why is it a negative externality?c0 Use a diagram to explain how the market fails with this externality
d) Using information from the clip, discuss the extent to which legislation is effective in reducing the negative externality