Part I of the manual is an introductory section. It sets out the definition of SEA, the objectives and benefits of conducting SEA, when SEA should be conducted and who has a duty or obligation to undertake SEA. The section illustrates that benefits and values would be added to the formulation of policies, plans and programmes and lead to environmentally sustainable outcomes when SEA is applied properly at the earliest possible stage, coincided with the formulation of policies, plans and programmes. The goal is to provide adequate, timely and useful environmental information when crucial decisions are made.