A deep depression is a well-developed low-pressure system that forms over the sea and pulls vast amounts of moisture inland. This moisture often results in heavy rainfall and strong winds. For example, a recent deep depression formed over the Bay of Bengal and moved westward, causing heavy rains across Odisha, Jharkhand, and Chhattisgarh. Although it weakens as it moves inland, it continues to fuel the monsoon flow, leading to widespread rainfall in northern regions.