They solemnly march the bodies up leafy Malabar Hill to the Towers of Silence, in an ancient ritual indifferent to the clamor and clash of modern Bombay.
Wrapped in white muslin, the dead are placed on slabs of marble, where they are devoured and dehydrated by the vultures and the heat of the sun. On the fourth day, the soul joins the spiritual world to reap the fruits or face punishment for what its owner had sown on earth.
But the vultures of Bombay are nearly extinct. And sunlight is weak during the three-month monsoon season.
That dilemma stoked by the unstinting march of time and technology has divided reform and orthodox members of the world's oldest prophetic religion. Reform Parsis are improvising with solar panels to dispose of their dead, a technique deemed sacrilegious by orthodox elders.
In multicultural India, home to a billion-plus people, mostly Hindus, Parsis are one of hundreds of ethnic groups. For the most part, these groups manage to live side by side, respecting and rejoicing in their different faiths.
"We are Indians first and Indians last, but in between, we are Parsis," says Noshir Dadrawala, head of the Centre for Advancement of Philanthropy. "We are loyal and patriotic, but as a community we also want to be true to our religion."
About 82,000 Parsis live in India, most of them in Bombay, comprising the world's largest group of Zoroastrians, followers of the Bronze Age Iranian prophet, Zarathushtra.
For the average 300 Parsis born in Bombay each year, 900 to 1,000 die. The odds are not in their favor. And, even in death, the Parsis are still at odds.
To Hindus, the vulture is a sacred bird. Legend has it that the homely creature gave its life while trying to rescue Sita, the wife of India's most revered god, Rama.
To Parsis, the vulture is also precious, in that it has unwittingly helped release the spirits of their departed for centuries. Death is considered the temporary triumph of evil over the human body.
Parsis view fire as holy, the giver of light and life, so offering the dead to fire is a mortal sin.
"Burial, burning or drowning are not ritually permitted in our religion as that would mean we are contaminating the earth, the fire and the water," said Khojeste P. Mistree, a Bombay Parsi and Oxford scholar of Zoroastrian studies.
Further, he notes, natural decomposition is eco-friendly, while cremation contributes to the greenhouse gases eating away at the planet's protective ozone layer.
Parsis place their dead in a "dakhma," a consecrated Tower of Silence, to await the vultures. In Bombay, there are five Towers of Silence concrete amphitheaters, 88 feet in diameter, set on pillars within the 55-acre "doongerwadi," a lush garden cemetery that has stood atop Malabar Hill, the city's wealthiest neighborhood, since 1673.
But fewer than a dozen vultures remain.
Older Bombay Parsis remember being frightened by the flocks of vultures that would skulk above the doongerwadi when they were kids. Today, young Parsis have never seen one of the brooding birds.
And some influential Hindus of Malabar Hill complain of the stench of the decomposing bodies and want the cemetery moved.
Parsis, too, shudder at their departed laying exposed to the elements for weeks on end.
"In Bombay, where you have three Parsi deaths a day and bodies piling up right in the heart of the city, you have a real problem," said Jehangir Patel, editor of Parsiana magazine.
So, Parsis are doing what they always have done: being innovative. They recently installed four solar panels on their Towers of Silence, using modern technology to complement one of mankind's oldest funereal rites.
The initiative has launched a debate among the orthodox who believe the panels deviate from the strict Zoroastrian rites used for centuries, and reformists who counter they must improvise to survive.
Homi B. Dhalla, a Bombay Parsi and president of the World Zarathushti Cultural Foundation, is credited with introducing the solar solution. He shrugs off orthodox critics who accuse him of watering down their faith.
"The underlying principle of our faith is exposure to the sun to dispose of our bodies," said Dhalla, who insists the solar panels merely magnify and intensify the heat of the sun. "I'm a pragmatist. Now we have a solution. Accept it, or don't accept it."
Mistree rejects it, calling the solar system "a glorified toaster." He instead champions a proposal to construct an aviary to breed vultures at the cemetery so that the Parsis can retain their religious purity.
He said a member of the Parsi Council was working with Jurong Bird Park in Singapore in a proposal to train juvenile vultures to fly from an aviary to the Towers of Silence, then return to the refuge once they have eaten. This would help protect the birds from the ills of Bombay.
Dastur Firoze M. Kotwal, a 67-year-old Parsi high priest, believes the solar solution also violates Zoroastrian tenets.
"God's natural heat is different," said Kotwal, whose long white beard nearly reaches the big belly beneath his white gauze robes. "The wind, the sun, the rain, everything is working for a purpose. But when you collect this heat and burn the corpses with heat that is not natural, it's really a solar crematorium."
The solar panels have gained popularity as they are inexpensive some $4,000 a panel and relatively efficient. The panels heat up to some 250 degrees, a temperature Dhalla claims does not burn the bodies, only dehydrates them.
"It's a good stopgap measure until either Mother Nature or humans can bring back the vultures," said Dadrawala.
The Oriental White-backed and Long-billed vultures are nearly extinct in India, Pakistan and Nepal. The U.S.-based Peregrine Fund, devoted to conservation efforts for birds of prey worldwide, reports 95 percent to 100 percent extinction of vultures in South Asia in the last decade, an unprecedented and alarming rate.
What's killing the vultures is a mystery, though experts believe pesticides, stress from encroaching humans, visceral gout that damages the kidneys, or a new avian virus could be to blame.
Breeding vultures in captivity in an aviary, which has the support of many in the orthodox community, could cost nearly half a million dollars.
"Nobody has that kind of money and at the end of the day, nobody knows what the results would be," said Dhalla. "A single bird could get a virus and infect all the others. It's a very big gamble."
Darayus Tirandaz, who lives with his family in one of the upscale Parsi colonies of Bombay, said they all support the aviary and want their bodies consumed by the "fowls of heaven" at death.
"Every religion must improvise, but there are limits that should not go beyond the boundaries to actually change the religion," he said. "The solar panels do burn the bodies. If we want to preserve who we have been for thousands of years, it's worth spending the money to bring the birds back."