The ecological offences, like many other criminal offences are committed either to gain profits or by negligence of duties. The way of committing them might be primitive (e. g. discharging liquid waste to a river) or quite sophisticated, involving high levels of technical expertise (e. g. system of shutting off air pollution control filters to make detection difficult). The negligence of official duty is mostly associated with breaking regulations, failing to maintain installations in proper state of repair etc.