Thousands of low-caste Hindus converted to Buddhism and Christianity in protest against new laws in several Indian states that make such changes of religion difficult.
The ceremonies took place in the central city of Nagpur to coincide with the 50th anniversary of the conversion to Buddhism of Bhimrao Ramji Ambedkar, a low-caste Hindu and the founder of India's democratic constitution.
Buddhist monks in orange robes and Christian priests administered religious vows in separate ceremonies to about 10,000 Dalits, the politically correct name for those called "untouchables" in the past.
Several states governed by the ruling Hindu nationalist Bharatiya Janata Party (BJP) have introduced or strengthened laws to stop what it says are forced conversions, mainly by Christian missionaries.
Most of those who converted in one of the biggest inter-faith changes in years were poor villagers from the state of Maharashtra, where Nagpur is located.
"You are no more a Hindu. Say you will not worship any Hindu god or goddess. Say I will never go to a temple," a Buddhist monk asked the crowd to repeat with him.
While more than 9,000 people converted to Buddhism chanting Buddhist mantras, more than 500 others embraced Christianity by taking dips in a makeshift pool as part of the baptism process.
Under the new laws anyone planning to leave the Hindu fold, the country's majority faith, must obtain certificates from officials and affidavits from courts, stating they were converting out of free will and not by inducements.
Christian groups say these laws are aimed at curbing religious freedom and against the Indian constitution. The anti-conversion laws were condemned by Pope Benedict XVI this year.
"There is complete freedom in the constitution to pick up and follow any faith you chose. Today is the celebration of that freedom," said Joseph D'Souza, president of the All India Christian Council, who presided over the baptism.
"This is not about religion or conversion. It is about a constitutional right, the right to practice one's own religion," said Udit Raj, president of the Indian Justice Party.
Dozens of riot policemen were deployed at a public park in Nagpur where the mass ceremonies took place. At the park some Dalit activists burnt a copy of Gujarat's anti-conversion law.
A hardline Hindu leader said the conversions were "forced".
"What are they talking about? Our constitution guarantees freedom of religion, not forced conversion," Prashant Harpalkar of the Vishwa Hindu Parishad (World Hindu Council) said.
More than 16 per cent of India's 1.1 billion population are Dalits, who occupy the lowest rank in a 3,000-year-old Hindu caste system.
Though caste discrimination is outlawed and the government has reserved quotas in educational institutions and government jobs for Dalits, they still face social discrimination in many parts of India and even violence from higher caste groups.
Hindus form 80 per cent of secular India's population, Muslims more than 13 per cent and Christians less than 3 per cent. Religious minorities such as Sikhs, Buddhists, Jains and Parsis make up the rest.
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