Underwater divers work under the surface of water, with or without the aid of underwater breathing apparatus, to inspect, install, repair, and remove equipment and structures, conduct tests or experiments, rig explosives, photograph structures or marine life, collect various forms of aquatic life for commercial or research purposes, and find and recover missing items and persons.
(j)      Tasks include -
taking safety precautions, such as monitoring dive lengths and depths, and registering with authorities before diving expeditions begin;
checking and maintaining diving equipment such as helmets, masks, air tanks, diving suits, harnesses and gauges;
descending into water with the aid of diver helpers, using scuba gear or diving suits
working under water to lay and repair bridges, piers and harbour-wall foundations;
inspecting for suspected damage and making minor repairs to ships' hulls and underwater installations;
reporting on condition of wrecked ships;
removing underwater obstructions;
drilling holes for underwater blasting;
performing various underwater tasks connected with salvage work or recovering dead bodies;
gathering shellfish, sponges and other aquatic life forms
communicating with workers on the surface while underwater, using signal lines or telephones;
obtaining information about diving tasks and environmental conditions.