Mir, along with dozens of Congress activists, took out the protest rally from the party's headquarters at M A Road here and tried to march towards Raj Bhavan.
As they reached Banquet Hall, police swung into action and detained many party workers including Mir, former minister Taj Mohiuddin, Peerzada Mohammad Sayeed and MLA Sopore Abdul Rahid Dar, officials said.
They said the detained leaders were taken to Kothi Bagh police station.
"The Congress MPs in Lok Sabha were seeking answers to the questions raised by the people of the country. But what they (BJP) did was undemocratic. They tried to muzzle the voice of the people. It was a black day for democracy," Mir told reporters.
"The BJP seems to think that they have a majority in the Parliament and can do whatever they like. That they will not allow anyone to talk...This is undemocratic," he said.
"The Congress party will continue to be the voice of the people and will expose the government," he said.
