Water scarcity is a critical global challenge, especially in arid and semiarid regions. Fog harvesting has emerged as a promising solution; however, concerns about air pollution and bacterial growth in humid environments have raised doubts about the safety and sustainability of such systems. This study introduces a Janus mesh with asymmetric wettability on its two faces, fabricated through a simple and scalable method. The unique design of the Janus mesh enables the transport of water droplets from the superhydrophobic side to the hydrophilic side in a unidirectional manner, enhancing its fog harvesting efficiency. The mesh's photocatalytic properties not only elevate the fog harvesting rate to 4.7 kgm-2h-1 but also effectively purify the harvested water by removing organic contaminants (94%) and microbial impurities (99.98%). Additionally, its inherent bactericidal activity prevents biofouling, ensuring sustained efficiency in water collection. The mesh's self-cleaning abilities through photocatalysis maintain its surface integrity, promising long-term stability for fog harvesting applications. This technological advancement in fog harvesting offers a sustainable and economical solution to water scarcity concerns, addressing safety and sustainability issues associated with existing systems. By potentially transforming the livelihoods of communities struggling with water scarcity, this innovation paves the way for a more sustainable future.