Wearing away or removal of the paint film when scrubbed with a brush, sponge, or cloth.
Choosing the wrong sheen for the area
Use of lower quality paint
Use of an overly aggressive scrub medium (see also Burnishing)
Inadequate dry time allowed after application of the paint before washing it
Areas that need frequent cleaning require highly washable premium quality paint formulated to provide such performance. High traffic areas may require a low sheen, semi-gloss or gloss paint rather than a flat/matt paint to provide good scrub resistance.
Allow adequate dry time, as scrub resistance will not fully develop until the paint is thoroughly cured. Typically, this will be one week. Try washing the painted surface with the least abrasive material and mildest detergent first. Dulux recommends range to maximise the scrub resistance of interior surfaces.