Depleting sources of mineral-based oils and environmental issues are pushing the research community for the development of sustainable, environmentally friendly bio-lubricants. However, the primary obstacle to the use of bio-lubricants in industrial applications is their limited lubricating capacity. Nanomaterials are major additives for lubricating oil to improve their lubricating properties. Halloysite nanotubes (HNTs) are naturally available, non-toxic nano-material. In this study, Halloysite nanotubes in five different proportions were blended with castor seed oil for enhancement of tribological properties. The interaction effect of load and Halloysite nanotube addition is considered for improving the load-carrying capacity and frictional property of castor seed oil. The recently proposed best holistic adaptable ranking of attributes technique (BHARAT) is implemented to obtain the optimal level of load and Halloysite nanotubes addition. Experimental results of tribological tests are analysed with the BHARAT approach proposing a 600N load and 1.5% Wt. of Halloysite nanotube addition in castor seed oil is optimum to improve the tribological properties of castor seed oil. The outcome of this study presents an environmentally friendly, sustainable bio-lubricant with improved tribological properties. The article also gives us insight into the innovative BHARAT approach for optimization in tribological studies.