The aim pursued by this Directive is the protection of the environment against the harmful effects caused by the discharge, treatment or deposit of waste oils. For the purposes of these provisions waste oils shall mean any liquid or semi-liquid used products totally or partially consisting of mineral or synthetic oil, including the oily residues from tanks, oil-water mixtures and emulsions. Member States must take all necessary measures to ensure the safe collection and disposal of waste oils. In particular, they shall ensure that the disposal of waste oils is carried out by recycling (art. 3). The following are to be prohibited by Member States: (1) any discharge of waste oils into internal surface waters, ground water, coastal waters and drainage systems; (2) any deposit or discharge of waste oils harmful to the soil and any uncontrolled discharge of residues resulting from the processing of waste oils; (3) any processing of waste oils causing air pollution which exceeds the level prescribed by existing provisions. Article 6 prescribes that any undertaking which disposes of waste oils must obtain a permit. Such undertakings must be inspected periodically by the competent authorities designated by Member States. Moreover, article 10 provides that any establishment producing, collecting or disposing of more than a given quantity of waste oils per year, to be specified by each Member State but not higher than 500 litres, must keep a record of the quantity, quality, origin and location of such oils and of their despatch and receipt as well as convey such information to the competent authorities on request.