Pope John Paul II, ignoring threats of demonstrations by Hindu nationalists, set off yesterday on a 10-day trip to India to raise the banner of Christianity in the vast Subcontinent, where Christians are a tiny, if ancient, minority.

Having already traveled around the world more than any pontiff in history, the pope plans 14 stops across the subcontinent, home of about 12 million Catholics.

The pope arrived in New Delhi early Saturday amid tight security, Reuter reported.

Aware of the sensibilities of India's proud Hindu majority, whose extremist groups in New Delhi, Goa and Bombay already have threatened demonstrations against his visit, the pope plans to begin his trip with a major message of peace delivered at New Delhi's monument to Mohandas K. Gandhi, the apostle of nonviolence who was the father of Indian independence in 1947.

During 2 1/2 days in the Indian capital, the pope will meet with Prime Minister Rajiv Gandhi and other state officials as well as with India's 124 Catholic bishops and say an open-air mass in Indira Gandhi Stadium. Then the pope will fly to the Jesuit mission in Ranchi, in impoverished Bihar State, and on to Calcutta, where he will visit Mother Teresa, the Nobel Peace Prize laureate.

From Calcutta the pope will fly to troubled Assam State, sandwiched between China and Bangladesh, to visit another Catholic missionary center at Shillong. Then he will fly to southern Tamil Nadu and Kerala states, the heart of Indian Catholicism, before winding up his visit with trips to Goa, Manganore, Bombay and Pune.

Opposition to the papal visit was expressed publicly two weeks ago by the militant Hindu leader Vikram Savarkar, president of the All-India Hindu Congregation, who charged that the pope was coming to India to "help the conversions" of Hindus to Christianity. In New Delhi yesterday, a crowd estimated by police at 10,000 demonstrated against the visit, shouting, "Pope go home."

Although the first Christian church said to have been founded in the southern state of Kerala by the Apostle Thomas in A.D. 52 has remained an Indian institution, the European missionaries who came after Portugal colonized Goa in the 16th century gave Christianity on the Subcontinent a non-Indian character resented by nationalists and Hindu fundamentalists.

At the root of the conflict have been fears, expressed by Savarkar, of Catholic conversions of Hindus. Vatican officials dismiss the Hindus' concerns by stating that Catholicism has made almost no inroads on Hinduism over the centuries and that whatever evangelization has succeeded in India in recent times has taken place among non-Hindu, animist tribes in northeastern states such as Bihar and Assam.

"The fact is that the number of Catholics in India has remained constant at a little over 1.5 percent of the population for as long as I can remember," said the Rev. Jacques du Puis, a Belgian Jesuit who spent 40 years in India before returning to Rome as a theologian at the Jesuits' Gregoriana University. "I don't believe anymore that India will ever become a Christian country."

The threat of trouble is being played down by Vatican officials and the Catholic hierarchy in India despite India's history of communal violence and the fact that both Mohandas Gandhi, the country's revered founder, and Indira Gandhi, the current prime minister's mother and predecessor, were assassinated by religious fanatics.

The Rev. Roberto Tucci, the organizer of the papal pilgrimages and their security, said at a press conference this week that he was not overly concerned about the threats of demonstrations. He said that, as in the papal trip to the Netherlands last year, the protests probably would be strongest in the least Catholic cities and therefore "will only be on the margins of the visit."

Even so, two white, open limousines protected by shields of bulletproof glass behind which the pope can stand as he drives through crowds, have been flown to India for his use. Tucci said, however, that the limousines probably would be available for use only in Delhi, Bombay, Goa and Cochin because of the difficulty of transporting them.

The Indian government has taken total charge of security for the pope's visit, and he will be flown around India in a government plane with the same complement of security that normally accompanies Prime Minister Gandhi. Vatican officials said they hoped that trouble would be avoided because of the Indians' traditional reverence for religious leaders.