**2. Theoretical underpinning**

It is undeniable that the environment within which tourism and its sub-sets operate has completely been transformed from 'a normal sectoral environment characterised by optimistic economic prospects' to 'a new normal environment characterised by uncertain economic prospects' due to the advent of global health crises and their subsequent stringent precautionary measures [22]. In this context, the business theory (BT) posits that the success of a business organisation is determined by assumptions relating to its environment, the accomplishment of its mission, and competencies and resources that enable the fulfilment of its mission [23]. The business theoretical perspective is based on flexibility, hence it makes provision for business organisations to review their key assumptions when unprecedented business opportunities or threats arise [24]. According to this theory, the aspirations of any business venture, including NBT, are based upon strategic intent that is communicated through its vision, mission, and goal statement [25]. It thus provides a foundation for practitioners and policymakers to develop strategies to sustain tourism businesses amid global hazardous phenomena. In tandem with sustainable behaviour, this theoretical perspective elucidates various challenges within the tourism industry [26, 27] and can facilitate the revitalisation of rural areas as it encourages the protection of residents' quality of life, the preservation of traditional cultures, environmental conservation, employment creation, and income generation [28]. The social exchange theory (SET), which is useful in analysing social behaviour and linking sociology, social psychology, and anthropology [29] also underpins the discourse. SET underscores interactions and commitments [30] that depend on strong relationships under certain conditions, such as tourism operations amid global hazardous phenomena [31]. For example, empirical findings by Gumede and Mdiniso [32] reveal that domestic and international tourists who visited South Africa's tourist sites during and in the wake of COVID-19 had to comply with this country's stringent safety protocols. This theory explains human-resource interactions and tourist destination perceptions [33], while it also examines relationships among various residents [34]. This chapter thus argues that, in the wake of unprecedented global health crises, sustainable NBT is predicated upon the business theory as well as the SET of development.
