Recently, TiO 2 nanotubes (NTs) have gained enormous research interest and the quest to enhance their photocatalytic properties and performance for the gaseous pollutants� removal, especially formaldehyde continues. Several synthetic routes have been adopted for fabrication of TiO 2 NTs. As the development in this area of research in nanotechnology nowhere seems to retard with increasing concerns due to the presence of toxic formaldehyde in indoor environment, the fabrication or synthesis approaches for growing TiO 2 NTs are becoming more relevant than ever. In that aspect there is a dire need for critical assessment of the current perspective on synthesis routes and their ability to present a solution for the primary challenges of utilizing toxic solvents and expensive fabrication procedures and facilities. The present review gives a meaningful insight into the fabrication routes for TiO2 NTs and highlighting the key finding from previous studies, thereby identifying the core challenges and strength of existing techniques. The state of the art is elaborated along with an all-inclusive review on the mechanism of nanotubes formation and photodegradation of formaldehyde by TiO 2 NTs. A group of emerging ionic-liquid based electrolytes known as deep eutectic solvents for TiO2 NTs fabrication were identified as the potential electrolytes to overcome the limitations of the existing methods. Conclusive research needs in the above mentioned aspects are suggested accordingly. © 2021 Elsevier B.V.