Hundreds of thousands of low-caste Hindus, known as Dalits, have held a mass rally in India's financial capital Mumbai (Bombay).
The meeting was to mark the 50th anniversary of the death of their leader, BR Ambedkar.
Security was tight because Dalit protesters rioted last week after a statue of Dr Ambedkar was vandalised in the northern city of Kanpur.
At least three Dalits were killed and trains, cars and property were damaged.
The meeting was held in central Shivaji Park close to where Dr Ambedkar was cremated 50 years ago.
The park was packed with followers who had come from all over India to pay their homage to a man who fought against discrimination on the basis of caste.
His followers, who were called untouchables, say that caste discrimination still existed in rural India.
One man said he was not allowed to worship in his village temple which is dominated by higher caste priests.
The authorities expected over 1.5 million people to visit the venue before the ceremony ended on Wednesday night although it appears the turnout was lower than that.
Senior police official Arup Patnaik, told the BBC that the police were on "high alert" and every policeman's leave had been cancelled for the day.
Mr Patnaik said the authorities had taken last week's incidents "into consideration" and additional paramilitary forces had been stationed at various places in Mumbai.
All police leave has been cancelled for the rally
Police had asked the state government to declare 6 December a holiday but the administration decided against it, he added.
However, as a safety measure, schools and colleges were granted permission to remain closed.
On Monday, police prevented leaders of the Republican Party of India - made up of low-caste people - from staging a rally in the central Indian town of Nagpur.
Dr Ambedkar, a Dalit himself before converting to Buddhism, was the chief architect of the Indian constitution and enjoys iconic status among the people of the community.
Dalits used to be known as untouchables, and were not included in the Hindu caste system, which has existed for thousands of years.
While the caste system has been outlawed by the constitution, many Dalits still claim they are discriminated against and remain economically disadvantaged.
Meanwhile, in the southern state of Karnataka, police fired tear gas shells and used canes to disperse Dalits protesting at the desecration of the statue of BR Ambedkar in Kanpur.
Police said the protesters burnt two buses and damaged at least eight more.