Regulations can tell governments and business what they can and cannot do in detail, or can set less precise goals. Authorities can monitor pollution at the point of discharge – ‘end-of-pipe’ – or watch the state of the environment after emissions. The more regulations are agreed with those who have the potential to damage the environment, the less it is likely to cost a government. Regulations must be rigid enough to avoid enforcement problems – especially costly legal arguments – and to prevent evasion, and they must also work in practice.