Even, important establishments like the Divisional Commissioner's office and the DIG's office in the city are now under threat, according to official reports.

The illegal work by some unscrupulous quarters continues despite government restriction and protests by local people.

At least 30 dredgers are engaged in sand extraction illegally from the river in the city and its outskirts.

The government is also deprived of huge amounts of revenue.

These sand traders, backed by powerful quarters and a section of corrupt officials, are lifting sand using so-called 'licenses' from the Bureau of Mineral Resources Development (BMRD).

But, sources said they are taking advantage of loopholes and lack of transparency in the licences. Even, at places, they do not bother to renew the licences, the sources claimed.

To stop the illegal work, a committee was formed last year with the Additional Deputy Commissioner (Rev) as its convener. It includes officials of PWD and WDB.

The committee after visiting different affected areas submitted a report stating irregularities regarding issuance of lease and loss in government revenue, in addition to the serious environmental damage.

The report said, due to indiscriminate extraction of sand from Surma river, the historical Keane Bridge and offices of the Divisional Commissioner and the DIG of police may be in danger.

The Cabinet Division issued a circular on September 30 last year stating that an inter-ministerial committee headed by the Secretary of Inland Water Transport Ministry only can give permission for dredging. No other authority or department has the authority to issue permission for dredging, the circular stated.

But, the WDB and the BMRD without doing any hydrological survey, often issue licences for sand collection, sources said.

Acting on the committee report, the Sylhet Deputy Commissioner had sent a confidential report to the ministry's secretary with a request for action against the Acting Director of BMRD, which had issued the licences in December last year.

Meantime, the BMRD stated that no permission was given for using dredgers to collect sand from riverbeds or quarries. But, in all the places, random use of mechanised dredgers is going on.

Even, at places, several kilometres of pipeline have been laid to take the extracted sands to raise lands for commercial purposes. They have already filled up huge water bodies and low lands in areas like Mendibag, Sobhanighat, Khadim, Parairchak Rafipur, Mollagaon.

It has been observed that at times, sand lifting had remained suspended for some days at places after steps by the district administration. But it resumed soon after.

In some cases, the lessees filed writ petitions for temporary injunction on orders for stopping dredging.

It is also alleged that government attorneys do not play their proper role, keeping the scope for looting by the licence holders.

The land ministry also ordered steps against real estate developers in Sylhet months ago, but no action has yet been taken by the local administration, it was gathered. The land developers continue to develop lands with sands collected from the Surma riverbed, using pipeline.

An official in the district administration seeking anonymity told The Daily Star that the government has incurred a huge amount of loss in royalty and taxes. The Assistant Commissioner of Sylhet Sadar issued notices to the licence holders for payment of government royalty, but to no effect.