The entire coastal belt of the Indian peninsula is considered highly corrosive. Steel and other ferrous metals along the coastline are particularly susceptible to corrosion, primarily due to chloride ions present in sea salts. This process is further accelerated by atmospheric oxygen, which diffuses through the moisture film to reach the metal surface.

Corrosion of reinforcing steel is a major cause of concrete deterioration in coastal environments. High-permeability concrete, poor design detailing, and construction defects—such as inadequate cover depth—allow salt and moisture to penetrate the concrete. The resulting high concentrations of salt and moisture accelerate steel corrosion, significantly compromising the integrity of the structure.

Concrete structures in coastal areas experience varying degrees of corrosion depending on their exposure levels. These can be categorized into three zones: the submerged zone (below seawater), the splash and tidal zone (intermittently wet and dry), and the atmospheric zone (above the high tide level). Each zone exhibits distinct corrosion characteristics. Corrosion below the waterline is limited due to low oxygen availability, while above the high tide level, lower chloride and moisture content restrict the corrosion rate. However, the splash and tidal zones face the most severe corrosion, as alternating wetting and drying cycles lead to high chloride and oxygen levels. 

Atmospherically exposed structures, such as buildings, are vulnerable to corrosion from airborne salts and atmospheric moisture. The quality of concrete and the depth of cover play a crucial role in chloride ingress. Therefore, protecting both new and existing structures with proper coatings is essential for enhancing durability.