According to recent reports, Shraddha Kapoor who is a trained diver and Sidharth Malhotra who loves scuba diving, shot for seven hours continuously underwater, while shooting the Galiyan song for Ek Villain. The actors had French divers carrying oxygen cylinders following them.
However, experts say that it is not possible to stay underwater for so long. Prahlad Kakkar, ad filmmaker, certified diver and owner of diving school in Andaman, says, "One can stay underwater maximum for 30-45 minutes depending on what mix of compressed air you are using. The longer you stay, the more bits of nitrogen your body absorbs and because you are under pressure the nitrogen becomes soluble in water as opposed to land where it can't enter the body as it is not soluble. The more the atmosphere becomes deeper, the more soluble nitrogen gets. Your body becomes like a soda water bottle with bubbles in it. The longer you stay, the more bubbles you develop and if you don't come up and allow the pressure to release you may develop bubbling Divers Bend where everything turns painful from your nervous system to your joints. You may also develop de-compression fitness symptoms and that's why you have to train your breathing. To say that one can stay for seven hours underwater is stupidity!
When you report inaccurate stuff, problem is someone may try it out and could even die. When you are underwater for a long time there is a big artificial chamber with a little decompressed capsule bed on it with oxygen and normal air. To reduce the pressure and let it gently come back to normal after saturation, the divers must keep going to the decompression chamber for little breaks. Or one can carry air tanks with a compressed air mixture of oxygen, nitrogen and carbon dioxide. The oxygen turns toxic at 10 minutes and the oxygen cylinder can kill if you use up the air and will stop breathing. One can stay underwater for longer hours if one uses store-filled bottles one day before and keep changing them but it's not safe and highly risky. Workers/divers who work for three-four hours underwater and don't come up to the surface, take a month off every 15 days.
Sumer Verma, certified diver and deep sea photographer also refutes the seven hour claim. "The story sounds exaggerated. It is possible to stay in shallow depths for longer hours but one can get exhausted and dehydrated. Also, what they were carrying are not called oxygen tanks but air breathing apparatuses. I have shot in pools from 8 am to 8 pm, but even in shallow waters people do come up. I guarantee that they couldn't have stayed underwater for seven hours and were forced to come up to take breaks even if they were shooting at depths of 1 metre. It wasn't as if there was no need to come up for air."