Kolkata, Dec 24 (IANS) Lok Sabha Speaker Meira Kumar Friday expressed "grave concern" about corruption in corridors of power and urged the executive, judiciary, legislatures and the media to always remain alert and above board.

"Corruption is a serious issue. Especially when there is corruption in the hierarchy, among the public servants such as executive and legislatures. Then, common people's faith gets shattered. It is an issue of grave concern," said Meira Kumar when asked about peoples' representatives getting involved in various scams.

The opposition has been castigating the Congress-led United Progressive Alliance (UPA) government for several alleged instances of corruption, including the Adarsh society scam in Mumbai, the Commonwealth Games scandal and the irregularities involved in the award of 2G spectrum.

"We have four pillars of the state - executive, judiciary, legislature and media. The country will progress if people have undisputed faith on these four pillars. The people who are associated with it should always remain alert and conscious that they are above board," Meira Kumar said.

She was speaking at an interactive session jointly organised here by the Bharat Chamber of Commerce, the Calcutta Chamber of Commerce, the Indian Chamber of Commerce and the Merchants' Chamber of Commerce.

The opposition has been demanding a joint parliamentary committee (JPC) to probe alleged irregularities in the allocation of 2G spectrum which caused huge losses to the national exchequer.

Proceedings in both houses of parliament were disrupted through most of its winter session over the opposition's demand for the JPC and the government's refusal to give in.