Wearing black clothes, several opposition MPs on Monday took out a march from parliament to Vijay Chowk to protest against the government over the Adani issue and Rahul Gandhi's disqualification from the Lok Sabha.

The protesters, including Congress MP Sonia Gandhi and party chief Mallikarjun Kharge, gathered near the statue of Mahatma Gandhi in the Parliament complex and raised slogans against the government.

Holding a huge "Satyamev Jayate" banner and placards with "save democracy" written on them, the MPs proceeded towards Vijay Chowk where they staged a sit-in.

"How has Adani's wealth multiplied so much in the last few years. When you are going to foreign countries how many times have you taken the industrialist with you. The PM has not been able to give answers to questions raised against Adani," Kharge told reporters at Vijay Chowk.

"We want a JPC on the Adani issue. Why is the government not agreeing to this? Why are you scared of a JPC probe... it means 'dal mein kuchh kala hai' (something is wrong)," he said.

The opposition has been seeking a joint parliamentary committee probe into the allegations of corporate fraud and stock price manipulations against the Adani Group.

Kharge also raised the issue of Rahul Gandhi's disqualification as MP after a Surat court convicted and sentenced him in a 2019 criminal defamation case.

"You want to defame Rahul Gandhi that is why you transferred the case to Gujarat even as the comments were made in Kolar in Karnataka. Today is a black day for democracy," Kharge said.

Kharge said opposition MPs were dressed in black as the prime minister is "finishing" democracy.

Trinamool Congress, which has so far stayed away from opposition protests, joined the sit-in on Monday.

Earlier, MPs of various opposition parties, including Congress, TMC, BRS, and SP, met at the Parliament complex to discuss a strategy to take forward the Adani issue as well as Rahul Gandhi's disqualification matter in Rajya Sabha and Lok Sabha.