By Asit Jolly
BBC correspondent in Chandigarh
More than 300 hybrid lions housed in zoos and safari parks across India will be prevented from reproducing and allowed to die out over the next few years.
Many cross-bred lions are emaciated and weak
The country's Central Zoo Authority (CZA) has ordered all establishments holding Asiatic lions which have been mated with African lions to be sterilised so that they become extinct.
The authorities say the hybrid lions have weakened the blood pool of India's lions and have turned out to be mangy, emaciated and suffering from mental and physical defects.
Officials say it has now been recognised that the breeding programme - which started in the late 1970s - has been unsuccessful.
Critics say that the breeding programmes across India were largely unsupervised over the years.
The end result has been a large increase in "cocktail" lions that have been interbred and are genetically weak.
The hybrid animals bear characteristics of both species, but are low on immunity and prone to disease. Some are reported to be suffering from tuberculosis.
Experts say the cross-breeding programme began when captive Asiatic lions in India's zoos were cross-bred with African lions travelling in circuses.
The lions are prone to disease
In the early days, zookeepers were not made aware of the importance of conserving pure genetic stock, and resorted to prolific breeding so that more animals could be used for exhibition purposes.
Punjab's Chhatbir Zoo, near Chandigarh, was at the forefront of the programme, producing nearly 100 cats, many of which have since become sick and died.
"The breeding programme between Asiatic and African lions in zoos, and their subsequent further inbreeding since the mid-1980s, has weakened the bloodline and devastated their gene pool," Chhatbir Zoo director Kuldip Kumar said.
The zoo's once healthy pride of lions is now no more than a motley collection of disease-prone animals barely able to stand up.
According to zookeepers, almost 45 lions have died over the past three years.
"We lost 13 cubs in one go," remembers wildlife warden Neeraj Gupta.
Almost all the deaths occurred because the animals suffered from severe immune deficiency which slows down or prevents healing whenever the animals fall sick or are hurt.
Today, Chhatbir Zoo is left with just 30 lions, and nearly all of them are hybrid and suffer afflictions caused by inbreeding.
While the zookeepers do their utmost to treat the animals and keep them as comfortable as possible, there is little they can do for those born paralysed or for others whose open wounds refuse to heal.
Indian laws and tradition forbid the killing of animals, so the unhealthy lions will be allowed to die out rather than be culled.
"This is not so much a sad story about a failed cross-breeding programme, as it is a story about animal welfare," said Belinda Wright, executive director of the Wildlife Protection Society of India.
"Many of them are terribly sick including the young ones.
All male lions have been sterilised to preserve Asiatic stock
"Although they are kept in reasonable conditions - mostly in open areas - too many of these lions were bred and the over-crowding made them even more vulnerable to illness."
Wildlife officials say plans are now afoot to replace the captive lion population with pure Asiatic stock, possibly through fresh breeding programmes using animals from the Gir Wildlife Sanctuary in the western Indian state of Gujarat.
"Fortunately these are still available," said zoo director Kuldip Kumar.
To achieve this aim within the next decade, all male lions have been sterilised to prevent any further breeding of hybrids.
But in the meantime the once terrifying roars of lions at Chhatbir - like other Indian zoos - have been reduced to heart-rending wails.