The four villagers from the lowest Dalit caste were assaulted in western Gujarat state by ‘gau rakshaks’ (cow protectors) who were protesting against the skinning of a cow, an animal considered sacred by India’s large Hindu population.
Cow slaughter and the consumption of beef are banned in Gujarat and several other states in officially secular India.
“We have arrested three of the six accused on charges of attempt to murder,” N.U. Zala, a local police officer said.
The video shows the four half-naked men tied to a car as the activists take turns to thrash them with belts and batons at a crowded marketplace.
Two more Dalits were beaten up after they tried to save the other four.
Police said the low-caste workers brought the cow for skinning after it had died naturally.
Attacks by vigilante groups on cow traders and smugglers have increased since Prime Minister Narendra Modi stormed to power in 2014.
Right-wing Hindu groups in India have long demanded a complete ban on the slaughter of all cattle, citing religious scriptures.
At least five Muslim men were killed last year by Hindu mobs on suspicion of eating beef or smuggling cows across the country.