In low- and middle-income countries, expanding access to diagnostic testing and antiretroviral therapy (ART) is a key strategy in achieving the UNAIDS 2030 goal of eliminating the AIDS epidemic as a public-health threat by 2030. In patients experiencing virological failure of ritonavir-boosted protease-inhibitor (PI/r)-based second-line HAART, a sizable percentage do not harbour mutations within the protease (PR) gene (PI DRMs), indicating that resistance is mediated by other factors. Data on this issue remain scarce in the context of India’s expanding ART programme.