Some face additional charges including causing mischief, rioting and illegal assembly.
Defence lawyers on Wednesday condemned the charge as a violation of the constitutional right to "worship and assemble", and urged the court to dismiss the case.
Prosecutors said all of the accused were responsible for the head injury sustained by the policeman during a demonstration on November 25 near a Hindu temple just outside of Kuala Lumpur.
On Tuesday, Abdul Gani Patail, Malaysia's attorney-general, said Dadi had received stitches on his head after being attacked with bricks and iron pipes.
"This has nothing to do with race," he had said. "We follow the law. It applies to everyone under the sun."
Malaysian law prohibits public rallies without police permission but that did not stop tens of thousands of ethnic Indians from staging a massive protest rally calling for equality.
Riot police broke up the demonstration by firing tear gas and chemical-laced water cannon into the crowd after they refused orders to disperse.
Ethnic Indians, who make up eight per cent of the country's 27 million people, say they suffer discrimination because of an affirmative action policy that favours Malay Muslims in jobs, education, business and government contracts.
They say the government has denied them their religious rights, citing the demolition of dozens of Hindu temples by authorities.
Rejecting the allegations the government is instead accusing rally organisers of trying to inflame racial tensions in multiethnic Malaysia.