Question: In order to be scuba diving certified, do you need to know how to clear water from a mask?
About the article "Scuba diving", section "Scuba diver training and certification".

Candidate passages:
Diving masks and helmets solve this problem by providing an air space in front of the diver's eyes.
The refraction error created by the water is mostly corrected as the light travels from water to air through a flat lens, except that objects appear approximately 34% bigger and 25% closer in water than they actually are.
Therefore total field-of-view is significantly reduced and eye–hand coordination must be adjusted.
This also affects underwater photography: a camera seeing through a flat port in its housing is affected in the same way as its user's eye seeing through a flat mask viewport, and so its operator must focus for the apparent distance to target, not for the real distance.
This is only relevant for manual focusing.
Divers who need corrective lenses to see clearly outside the water would normally need the same prescription while wearing a mask.
Generic and custom corrective lenses are available for some two-window masks.
Custom lenses can be bonded onto masks that have a single front window or two windows.
A "double-dome-ported mask" has curved viewports in an attempt to cure these faults, but this causes a refraction problem of its own.
Cylindrically curved faceplates such as those used for firefighting full-face masks produce severely distorted views underwater.
Commando frogmen concerned about revealing their position when light reflects from the glass surface of their diving masks may instead use special contact lenses to see underwater.
As a diver descends, they must periodically exhale through their nose to equalize the internal pressure of the mask with that of the surrounding water.
Swimming goggles are not suitable for diving because they only cover the eyes and thus do not allow for equalization.
Failure to equalise the pressure inside the mask may lead to a form of barotrauma known as mask squeeze. 
Scuba diving may be performed for a number of reasons, both personal and professional.
Recreational diving is performed purely for enjoyment and has a number of distinct technical disciplines to increase interest underwater, such as cave diving, wreck diving, ice diving and deep diving.
Divers may be employed professionally to perform tasks underwater.
Some of these tasks are suitable for scuba.
Scuba divers are highly trained to encounter situations in which they may face vertigo or even get tangled in seaweed.
To prepare for such events, Scuba divers face a very rigorous training process to handle themselves calmly.
There are a fair number of divers who work, full or part-time, in the recreational diving community as instructors, assistant instructors, divemasters and dive guides.
In some jurisdictions the professional nature, with particular reference to responsibility for health and safety of the clients, of recreational diver instruction, dive leadership for reward and dive guiding is recognised by national legislation.
Other specialist areas of diving include military diving, with a long history of military frogmen in various roles.
They can perform roles including direct combat, infiltration behind enemy lines, placing mines or using a manned torpedo, bomb disposal or engineering operations.
In civilian operations, many police forces operate police diving teams to perform "search and recovery" or "search and rescue" operations and to assist with the detection of crime which may involve bodies of water.
In some cases diver rescue teams may also be part of a fire department, paramedical service or lifeguard unit, and may be classed as public service diving.
Lastly, there are professional divers involved with the water itself, such as underwater photography or underwater filming divers, who set out to document the underwater world, or scientific diving, including marine biology, geology, hydrology, oceanography and underwater archaeology.
The choice between scuba and surface supplied diving equipment is based on both legal and logistical constraints.
Where the diver requires mobility and a large range of movement, scuba is usually the choice if safety and legal constraints allow.
Higher risk work, particularly commercial diving, may be restricted to surface supplied equipment by legislation and codes of practice.
Diving activities commonly associated with scuba may include:Most recreational scuba diving is done using a half mask which covers the diver's eyes and nose, and a mouthpiece to supply the breathing gas from the demand valve or rebreather.
Inhaling from a regulator's mouthpiece becomes second nature very quickly.
The other common arrangement is a full face mask which covers the eyes, nose and mouth, and often allows the diver to breathe through the nose.
Professional scuba divers are more likely to use full face masks. 
The international rules of competition contain the following four objectives for Sport Diving - firstly, encourage the further development of recreational scuba diving equipment and technique; secondly, promote scuba diving activities in localities that are remote from suitable diving sites or where open water activity may be prohibited by seasonal or adverse weather conditions; thirdly, to provide an opportunity for recreational scuba divers to practice and improve technique; and fourthly, the promotion of scuba diving carried out in swimming pools as a spectator sport for underwater diving enthusiasts. 
  Snorkeling ( to see corals and fishes )  Scuba diving   Boating  white water rafting Adventure sports.
You can hire an entire boat for around 1800rs/- (diwali time 2012 rate) It will take you for dolphin seeing, golden rocks, tsunami island (for water sports) and snorkelling if you wish even if you don't know how to swim, they have floats.
Beaches can be dangerous as currents are strong on shore and locals recommend not to wander in more than waist high.
Boat owners will stop the boat in deep water to allow a swim where the currents are less strong. 
  Hip boot – Hip boots, or waders as they are colloquially called, are a type of boot initially designed to be worn by river fishermen.
Waders (footwear) – Waders refers to a waterproof boot extending from the foot to the chest, traditionally made from vulcanised rubber, but available in more modern PVC, neoprene and Gore-Tex variants.
Diving mask – A diving mask is an item of diving equipment that allows scuba divers, free-divers, and snorkelers to see clearly underwater.
Wetsuit – A wetsuit is a garment, usually made of foamed neoprene, which is worn by surfers, divers, windsurfers, canoeists, and others engaged in water sports, providing thermal insulation, abrasion resistance and buoyancy.