Why Construction of roads and railway are difficult in desert and equatorial regions comment?

The construction of roads and railways in desert regions is challenging due to extreme temperatures, shifting sands, and limited water resources, which complicate material transportation and infrastructure stability. In equatorial regions, dense vegetation, heavy rainfall, and muddy conditions can hinder access and construction efforts, leading to increased costs and time delays. Additionally, both environments present unique ecological concerns that require careful planning and environmental assessments.