Green Earth Tech

But despite the ban on the drug's manufacture, it is widely available, according to BirdLife International, a global partnership of conservation organisations, which also quoted the study in a post on its website.

"Time has almost run out to prevent the extinction of vultures in the wild in India. The ban on diclofenac manufacture was a good start but a ban on the sale of diclofenac and other drugs known to harm vultures is vital," said co-author of the study Rhys Green.

"Efforts must be redoubled to remove diclofenac from the vultures' food supply and to protect and breed a viable population in captivity," lead author Vibhu Prakash was quoted as saying by the organisation.

The researchers estimated the numbers of white-backed vultures at 11,000 from tens of millions in the 1980s.

The long-billed vulture population is believed to be around 45,000, while the slender-billed vultures number around 1,000, the study said.

The study recommended setting up three more captive breeding centres for vultures, apart from an existing facility in northern India to save the birds.

Last year, the centre bred two chicks in the first such effort in the world, but the birds died within a month.

The centre said that it would press on with its conservation efforts despite the setback.

In India vultures also play a vital cultural role. Followers of the minority Parsi faith depend on them for disposal of their corpses. They consider the burial or burning of human remains to defile the elements.