FORM - 2 THE PATENTS ACT, 1970 (39 of 1970) & The Patents Rules, 2003 COMPLETE SPECIFICATION (See Section 10 and Rule 13) DILUTION THICKENING, LIQUID CLEANSING COMPOSITIONS HINDUSTAN UNILEVER LIMITED, a company incorporated under the Indian Companies Act, 1913 and having its registered office at 165/166, Backbay Reclamation, Mumbai -400 020, Maharashtra, India The following specification particularly describes the invention and the manner in which it is to be performed DILUTION THICKENING, LIQUID CLEANSING COMPOSITIONS Field of the Invention The present invention relates to liquid cleansing compositions which are suitable for washing of skin or hair, and which have a viscosity which increases during dilution. Background and Prior Art. The use of salts to thicken surfactant systems and enhance viscosity is described for example in CA 2,211,313. Typically, a so-called peak viscosity is achieved when salt is first added, and further addition of salt leads to viscosity reduction {this is known as oversalting). When the composition is diluted, the "oversalted" composition then increases in viscosity once more in a process referred to as "dilution thickening." Dilution thickening is a desirable property for liquid cleansing compositions such as skin or hair washing compositions because it reduces product wastage caused by the liquid product slipping between the fingers or being rinsed away before the consumer has had time to use it. Dilution thickening also improves lather quality and makes product dosage easier to control for the consumer. Dilution thickening also makes spreading of the product onto the skin or hair easier to control for the consumer. Generally the dilution thickening effect is achieved by using relatively large amounts of salt (e.g. greater than 5% by weight). A problem with using large amounts of salt is that this can lead to a cloudy, hazy or opalescent product, or a product which is prone to phase separation. US 6,919,303 describes how an associative thickener such as PEG-200 glyceryl tallowate or PEG-7 glyceryl cocoate lessens the amount of salt needed to induce dilution thickening to as low as 2% by weight. The present inventors have found that the use of a monoalkanolamide surfactant lessens the amount of salt needed to induce dilution thickening to as low as 1% by weight or less. US 6,919,303 mentions that its compositions may also comprise coconut acyl monoethanolamides as suds boosters, but does not indicate that such materials might play any role in the induction of dilution thickening. WO 01/40431 describes a dilution-thickening hand soap composition which can include as a viscosity builder an alkanolamide derived from a fatty acid, such as coco dietlianoiamide, at a level of between 6 wt % and 2 5 wt %. The application also exemplifies the inclusion of sodium chloride in the concentrate at levels of 7% upwards. WO 0 3/01427 5 describes a dilution-thickening liquid soap composition based on a particular amine oxide surfactant; specific examples are shown which include both sodium. chloride and cocamide diethanclamide at levels of 6% upwards. CJS 2005/0043193, WO 95/02664, WO 96/21721, WO 96/32464, US 2007/0287648 and WO 96/03483 all describe other diluticn- thicxening systems. Summary of the Invention The invention provides a liquid cleansing composition comprising: (i) 1 to 30% by weight, based on the total weight of the composition, of anionic surfactant; (ii) up to 5% by weight, based on the total weight of the composition, of amphoteric surfactant; (iii) up to 2% by weight, based on the total weight of the composition, of electrolyte; (iv) at least 0.5% by weight, based on the total weight of the composition, of monoalkanolamide surfactant, and