The change came several years ago for Maryam Arrakal. Her husband brought a black, all-covering abaya back to this steamy, subtropical town from the desert sands of Saudi Arabia.
It contrasted starkly with the pastel saris she normally wore.
But in the 12 years that her husband, Kunchava, had been running a Saudi fabric shop, he had become detached from this melting pot of Muslims, Hindus and Christians, and more drawn to the Saudis' strict version of Islam.
"I used to dress much more colorfully," said Arrakal, standing amid diesel fumes and frenetic auto-rickshaw drivers in Vengara's one-street downtown, a 7-month-old baby in her arms and a black cloak shrouding her figure. "But my husband brought this for me and prefers me to wear it."
The migration to oil-rich Persian Gulf monarchies of as many as one in five men from India's Kerala province has brought an influx of money that pays for food, shelter and education. It also funds dowries for their daughters and gifts for their wives.
But like many of the world's millions of economic migrants, the men bring back more than money.
In this case, they brim with provocative ideas about the proper way to worship. And they pay for plain green mosques with minarets and Arabic writing that are far different than the ornate and bulbous temples where Muslims have long worshiped here.
In Kerala, where Muslims are traditionally the poorest residents, those returning from the Persian Gulf say they are building pride in their community and connecting its members to the broader Islamic world. But others see the growth of sectarian politics and scattered religious violence as warning signs.
"Kerala was a place in India known for communal harmony," said Hameed Chennamangloor, a writer and former professor of English at the Government Arts and Science College in Calicut, the main city in the province's heavily Muslim north.
Historically, when rioting between Hindus and Muslims swept through India, Kerala remained calm.
Now, Chennamangloor said, "There has been a rise in fundamentalist tendencies among a certain segment of Muslims."
From 40 days to 4 hours
Trade winds across the Arabian Sea have carried merchants between the Persian Gulf and southern India since antiquity.
When they arrived after 40 days at sea, Arab traders would stow their ships within Kerala's network of inland waterways.
As the ships were loaded, the traders introduced local people to new ideas, melding the teachings of the Koran with local practices.
Over the centuries, Kerala developed a relaxed mix of cultures and religions. The old mosques where Muslims worshiped were indistinguishable from Hindu temples. Muslims, Hindus and Christians attended one another's ceremonies and festivals. The region's colorful Sufi-influenced Islam includes such customs as visits to jungle shrines and reverence for local saints.
But the weak economy forced many men to leave to find work. Filmmaker Abbas Pannakal said his late father boarded a rickety ship in 1970 for a journey to the United Arab Emirates that took two months and cost the lives of 17 passengers.
"At first only Muslims went," said Pannakal, who is making a documentary about Indian-Arab relations. "They were willing to risk everything because they had so little to lose."
As successive oil booms caused the Persian Gulf economy to soar, South Asians started migrating in droves. Air connections expanded. A trip to Saudi Arabia, Kuwait, Oman, Bahrain, Qatar or the United Arab Emirates was whittled to four hours.
Scholars and government officials in India estimate that expatriate workers send back at least $20 billion a year. About 50% of Persian Gulf migrants from India come from Kerala.
From the moment they arrive, migrants from Kerala are introduced to attitudes unknown at home. Some housing is for Hindus only; some employers openly prefer Muslims over Hindus or Christians.
Some migrant workers are invigorated by living in a country with a Muslim majority. Others less enthusiastic about their new home cling to their faith out of loneliness and a sense of isolation. But they find a different interpretation of Islam.
Arrakal's husband, Kunchava, 49, had little to do in his free time in Saudi Arabia but attend prayers and read the Koran. He gradually changed his views about life and faith, including how his wife dressed.
"In traditional Indian garb, the woman's stomach is bare," he said. "Islamic dress covers up all the body parts."
In study groups and at prayer gatherings throughout the Persian Gulf region, men such as Abdul Rahman Mohammed Peetee hammer away at Kerala's traditions. For them, paying homage to local saints or anyone other than God is sacrilege: The Koran and the sayings of the prophet Muhammad contain all that any Muslim needs.
"You must study the Arab culture," Peetee, a Kerala native, told a gathering on the sixth floor of an office tower in Dubai, United Arab Emirates.
The men howled in protest.
"Some Arabs behave worse than us!" one cried. "Why should we study them? We have our own practices and culture."
Peetee, a stout man with a collarless shirt buttoned to his neck, was relentless.
"These practices are established by society," he said. "Not by the Koran."
Religious foundations and wealthy individuals in countries such as Saudi Arabia also promote a more rigid version of Islam. Qatar and Saudi Arabia have government agencies devoted to the religious lives of Asian expatriates, often administered by preachers from their own communities.
The Persian Gulf version of Islam fits the expatriate lifestyle: They can practice their faith in drab dormitories and on breaks during long work shifts. And it sanctifies their newfound riches. The wealth obtained by South Asian Muslims in the Persian Gulf is interpreted by many as a reward for service to God.
"Being in the gulf you can see the miracles of God," said Mohammed Ismayli Olshery Kalathingal, a Kerala computer specialist at a Dubai bank. "You can see all the things here that you can't see in Kerala."
When it started out 28 years ago, the Markaz Sunni Cultural Center just east of Calicut was a tiny orphanage supporting 21 children. It has grown into an empire, with a complex of religious schools and colleges educating 10,000 students. Its orphanage is home to 1,700 children.
Indian law requires that the white-clad students take classes in math, science and religion. But after school, they fan out across Calicut proselytizing in favor of an austere version of Islam.
Though a charity, Markaz has real estate holdings, including shopping centers and hotels. Each year it sends 1,000 of its most devout students to the Persian Gulf region, mostly to work in Abu Dhabi, in the United Arab Emirates.
Increasingly, new mosques are led by clerics who trained in the Persian Gulf, though most are graduates of Indian seminaries.
More wealth has meant that more Kerala Muslims have the time to pray five times a day and more can afford a religious education for their children. The new mosques enforce strict separation of the sexes.
Impressed by the power of education, many returnees urge their daughters and sons to attend high school and college. But to placate their parents, women raised in conservative families often must abide by strict Islamic dress codes.
By the 1990s, Kerala clothiers began mass-producing cheap Persian Gulf-style religious coverings for women. Now they are worn even at universities.
"What the women wear depends on the trend in the gulf," said Fazel Kizhekkedath, a 24-year-old salesman at the Hoorulyn clothing wholesaler. "Now the trend is the abaya. Black is the new fashion now."
Men also are being told by religious groups what to wear. One Islamic organization recently demanded that Muslim youths stop watching soccer and wearing T-shirts with team logos.
N.G.S. Narayan, author of the foremost book on Calicut history, said he came face-to-face with the new attitude when he tried to conduct research at an old mosque. Thirty years ago he was welcome to restore and decipher ancient tablets. Recently he was turned away; non-Muslims were no longer allowed.
Once Hindus used to head Muslim organizations and vice versa. Now Muslim groups urge followers to keep their children away from Hindu ceremonies.
Muslim Indian scholars of the Deobandi school have preached similar ideas. But critics say the latest wave, fueled by Persian Gulf money, represents an Arab colonization of Kerala.
"I am scared," said one moderate Muslim newspaper editor, who asked that his name not be published because it could harm his community standing. "The liberal Muslims, the moderate Muslims, are scared."
The religious awakening also has given rise to a new political assertiveness.
Critics say Muslim organizations have set up de facto political machines, forcing parties on the left and right to woo extreme Islamic groups funded by Persian Gulf riches.
Although it denies any active political involvement, Markaz and its leader, Kanthapuram Abu Bakr Musaliar, have become major players in southern India.
"Now he's a kingmaker," Chennamangloor said. "He's got a vote bank."
Kerala's elders often boasted that Hindus, Muslims, Christians and a smattering of smaller religious groups were Indians first. Religious identity took a back seat to class interests. The Communist Party and the conservative Indian National Congress dominated elections.
During recent ballots in a Muslim enclave near Calicut, both the Communist Party and conservatives plastered walls with pictures of Saddam Hussein. Even before the controversy over his execution, Hussein's trial had become a cause celebre among Muslims, largely because of the region's connection to the Persian Gulf.
"Social life has been politicized," Narayan said. "Muslim community organizations found that they could corner all the Muslim votes."
Many worry that the status quo has begun to unravel.
In January 2002 and May 2003, 14 people were killed in riots between Muslims and Hindus in Calicut. And in February 2005, suspected Hindu nationalists attacked a mosque in the town of Vallikunnam at the end of evening prayers, killing one and injuring two.
"Muslims themselves are worried by the rise of the militant Islamic organizations," said Ajai Mangat, Calicut correspondent for the Malayalam Manorama, the province's largest daily newspaper. "If they become more powerful, the Hindu nationalists become more powerful."
Daragahi recently was on assignment in southern India.