Thousands of people have been attending mass ceremonies in India at which hundreds of Hindu Dalits converted to Buddhism and Christianity.
Thousands attended the conversion ceremonies in Nagpur
The events in the central city of Nagpur are part of a protest against the injustices of India's caste system, activists say.
The Dalits - once known as Untouchables - hope to escape the prejudice and discrimination they often face.
Laws designed to protect Dalit rights are ineffective, critics say.
The ceremonies mark the 50th anniversary of the adoption of Buddhism by the scholar Bhimrao Ramji Ambedkar.
He was the first prominent Dalit to urge low-caste Indians to embrace Buddhism.
As the chief architect of India's constitution, he wrote anti-discrimination provisions and quota systems into the country's law.
'Cry for dignity'
The Dalits arrived by the truckload at a public park in Nagpur for ceremonies, which began with religious leaders giving fiery speeches against the treatment of lower castes.
167m people, 16.2% of India's population
Nearly 60% live in Uttar Pradesh, West Bengal, Bihar, Andhra Pradesh, and Tamil Nadu states
The lowest rank in Hindu society, beneath the traditional caste system
Expected to perform the most menial jobs, particularly handling cadavers and human and animal waste
Physical contact with a Dalit was traditionally considered ritually polluting for other castes
Even converts to Christianity and Islam have encountered discrimination from higher-caste converts
Reuters reported that dozens of riot policemen had turned out at the sprawling park.
Udit Raj, a Dalit leader, told the BBC that around 2,500 people converted to Christianity and Buddhism.
Joseph D'Souza, the president of the Dalit Freedom Network and a Christian convert, described the conversions as a "celebratory occasion".
"I think it's important to understand that this is a cry for human dignity, it's a cry for human worth," he told the BBC.
He said that Dalits could seek dignity by converting to Christianity, Jainism or Sikhism as well as Buddhism.
Laws against conversion
Several states governed by the Hindu nationalist party, the BJP, have introduced laws to make such conversions more difficult.
Hundreds of Dalits converted to Christianity and Buddhism
The states of Rajasthan, Madhya Pradesh and Tamil Nadu have all passed laws restricting conversions.
Gujarat has reclassified Buddhism and Jainism as branches of the Hindu religion, in an attempt to prevent conversions away from Hinduism eroding the BJP's bedrock support.
Officially, caste discrimination was outlawed when India gained independence in 1947, but many of the country's 180m Dalits say that people's attitudes towards them remain the same.
They are still often expected to do the most menial jobs. In many villages, they are also prevented from drinking water from wells used by high caste Hindus.