http://www.bbc.co.uk/news/health-38506735
Edexcel spec reference
1.3.1 Types of market failure
1.3.2 Externalities
AQA Spec references
3.1.5.2 The meaning of market failure
3.1.5.4 Negative externalities
3.1.5.2 The meaning of market failure
3.1.5.4 Negative externalities