Chapter 11 examines environmental criminal law that aims to punish and deter unacceptable pollution to protect the environment and public health. Pollution used to be tolerated as a way of life. Now a distinction is drawn between ‘acceptable’ pollution by routine operation in compliance with state provisions and ‘unacceptable’ pollution in violation either intentionally or negligently committed to maximize financial gains. The latter is punished by administrative penalty or criminal sanction depending on the seriousness of circumstances. The chapter reviews early treatment of environmental crimes under the Criminal Law (1979), and examines the more sophisticated approach to environmental crimes under the Criminal Law (1997) including the crime of causing serious pollution accident, crimes relating to cross-border movement of waste and the crime of environmental dereliction of duty. It analyses the criminal law amendments on the crime of waste smuggling and the crime of environmental pollution. The chapter concludes with discussion of key issues of criminal law including legal person and natural person, fault-based liability, defences, sanctions balancing severe punishment with leniency, and liability of multiple parties jointly committing crimes.