Work in adverse environment demands assurance that safety procedures are followed to the highest international standards.Continuous monitoring of temperature and other critical parameters in zones inaccessible to human monitoring calls for a new generation of sensors which can withstand hazardous environment for long time.Optical fibers have shown the potential of extending their applications well beyond the telecommunication arena because of the unique advantage of tailoring their properties to make the fibers application specific through change in design and composition.This led to an extensive R&D effort for the development of specialty fibers well suited for a host of industrial, medical and strategic applications.One such area where optical fibers are found to have significant potential is application under radiation environment for data communication,multi-parameter sensing such as radiation, temperature, optical spectrometry etc.Thus, for work in such 'no-man-area', optical fiber is accepted as the most suitable candidate for use as data link to sensing.The performance of the complete sensor system depends on both the transmitting fiber and the sensor probe.However, ionizing radiation degrades the transmission of optical fiber significantly in the UV-Vis-NIR wavelength region through introducing radiation induced attenuation (RIA).This induced absorption is prominent in UV-Vis wavelength region, the tail of which extends to the NIR.The talk will cover the key challenges regarding the development of pure silica core fiber in the operating wavelength region of UV-VIS-NIR through MCVD process targeting application in spectroscopy and data communication as well as sensing in ionizing environment.This will review the journey of silica core optical fibers covering their design, material selection criteria, possible ways of fabrication, behavior of different fibers under ionizing environment and defect formation, required specification in terms of wave guiding and environmental tolerance for specific application, tested results of commercial fibers and the research outcome so far.Against this background, the fabrication process of silica core radiation resistant fiber through MCVD process as followed in CSIR-CGCRI and influence of fabrication process as well as the fiber drawing parameters on the formation of defect precursor will be explained.A fiber Bragg grating based strain and temperature monitoring in the adverse environment, effective for structural integrity monitoring using the fabricated fiber will also be covered in conclusion.