Pope John Paul II conferred privately today with the exiled Dalai Lama of Tibet, one of the world's key Buddhist leaders, then made an ecumenical appeal for all religions to collaborate in advancing "the cause of humanity" that joins them.

In the second day of a 10-day visit to India, the pope raised the banner of understanding among different religions in this nation of Hindus, Moslems, Buddhists, and half a dozen other religions. A scant 1.7 percent of the 745 million inhabitants are Catholic.

In the tightly guarded Indira Gandhi gymnastics stadium, where all of the pope's encounters with the Indian public have taken place so far, he said: "Today, as Hindus, Moslems, Sikhs, Buddhists, Jains, Parsees and Christians, we gather together in fraternal love to assert this by our very presence."

The pope addressed the crowd of about 15,000 despite an incident at the end of his mass in the same stadium earlier in the day in which a small firecracker was thrown from a public stand.

The firecracker, thrown by what security officials later described as a slightly "unbalanced" 33-year-old Catholic from the southern state of Kerala named Domenic Ouseph, exploded 50 yards behind the pope. A security officer said Ouseph had been detained, questioned, then released.

Hindu extremists have denounced the visit and vowed to oppose it. According to police officials, more than 400 Hindu demonstrators were detained yesterday after scattered protests against the pope's arrival.

In his speech, the pope dropped the traditional Catholic claim to preeminence as an interpreter of God and true religion. "To work for the attainment and preservation of all human rights, including the basic right to worship God according to the dictates of an upright conscience and to profess that faith externally, must become ever more subject of interreligious collaboration at all levels," he said.

Last month, the pope said he had appealed to the leaders of all major religions to join him in a communion for peace at the St. Francis of Assisi Cathedral in Italy. The Dalai Lama was understood to have given his assent.