A/HRC/34/26 is unable to ascertain whether the accommodation is relevant, more support information may be requested from the person concerned. The assessment must not be based solely on medical information, but rather on functionality, that is, focused on needs and existing barriers. States should design regulatory frameworks to prevent the cost of assessment from falling on the person concerned and to ensure that the assessment is performed by a relevant authority. (c) Objective justification of denial of reasonable accommodation 47. The requested party can deny an accommodation without incurring in discrimination on the basis of disability by demonstrating that it is either not feasible (legally or in practice) or relevant (“necessary” and “appropriate”), or that it would impose a “disproportionate or undue burden”. The justification of the denial must be based on objective criteria and analysis, and communicated in a timely fashion to the person with the disability concerned. 48. The above-mentioned criteria may be closely intertwined in practice, in particular during exchanges between parties, as needs, contexts and alternatives may be extremely diverse and contingent. Failure to meet one criterion may suffice, however, to justify the denial of reasonable accommodation without incurring discrimination (for example, if the accommodation is clearly not relevant to the exercise of the right at stake, there is no need to prove another element). 49. These criteria, as reflected in current national practices – for example as suggested in regulations in Belgium – include a set of different factors, which should not be considered exhaustive. Furthermore, they should take into account the right at stake and the context of the provision of reasonable accommodation. The factors to be considered must be clear, objectively measurable and neither vague nor ambiguous in order to avoid arbitrariness and prevent discrimination; for example, legislation should not include clauses such as “the moral of other employees”, “any other factor affecting efficiency, productivity, success and competiveness” or “overall economic climate”, as they do not allow for objective assessment. 50. Factors that are discriminatory, whether in law or de facto, due to their negative or disproportionate impact on persons with disabilities should be repealed. National practices discriminate against persons with disabilities when they include such criteria as “degree and kinds of effects on other students” (in education) or when productivity assessments for employment are applied only to persons with disabilities (or have a disparate impact on them owing to elements not related to the core aspects of the job, namely, without any objective justification). (d) Legally and materially possible 51. No person providing an accommodation may be obligated to breach the law. A request of reasonable accommodation should be made in accordance with existing laws, regulations or agreements. Practices in the United States of America, Canada, Australia and Belgium are clear in this regard. For instance, a requested party may deny an accommodation that entails the acquisition of certain products (for example, accessibilityrelated software) if its importation is not allowed by customs laws. States should include in their legislation the possibility of requesting waivers to allow for the provision of reasonable accommodation, including in private agreements. Requested parties should make efforts in good faith to obtain such waivers. 52. At the same time, a requested party may only provide accommodations that are materially possible; if the entity that is supposed to provide the accommodation proves that it is materially impossible, it would therefore not incur discrimination. An accommodation 12