New Delhi: Forensic medicine specialists say unintentional drowning claims hundreds of thousands of lives worldwide each year but point out that actress Sridevi's final tragic moments still remain a mystery.

One purported Dubai document has attributed the cause of her death to "accidental" drowning. Media reports from the UAE claimed "traces of alcohol" had been found in her blood.

Forensic medicine experts in India say the information available in the public domain till Monday evening is not enough to reconstruct the events.

"Many factors could make a person lose consciousness - alcohol may induce drowsiness or cause a person to stumble, loss of consciousness could also be brought about by an organic reason related to the heart or the brain," said B. Suresh Shetty, professor of forensic medicine at Kasturba Medical College, Mangalore.

However, Shetty said, since the report released in Dubai does not specifically mention organ-related abnormalities or any traumatic causes for loss of consciousness, "we could lean in favour of alcohol as a cause for the fall".

But Shetty cautioned that without information about actual concentrations of alcohol metabolites detected in the blood, even this would be "pure speculation".

The concentrations of alcohol metabolites in blood allow doctors to determine how much alcohol had been consumed and how long prior to death. The tests typically look for well-defined metabolites of alcohol that are not usually found in blood and cannot be explained through other ways.

The time taken for a person to die from drowning in a bathtub would depend on whether attempts to survive were made but is likely to be less than 10 minutes, Shetty said.

The Global Burden of Disease, an international exercise to estimate the myriad causes of deaths, had estimated that about 439,000 people had died worldwide from unintentional drowning in 2010 - in rivers, streams, ponds, the sea, swimming pools and bathtubs.

Japan had accounted for the highest proportion of unintentional drownings in bathtubs (65 per cent), followed by Canada and the US where bathtubs account for about 11 per cent of accidental drownings.

A study of 92 bathtub deaths over 11 years in the US state of Maryland had identified three main causes of bathtub drownings - cardiovascular disease, alcohol-related deaths and seizure disorders.