Forest office sources said the senseless act disregarding the government prohibition poses serious threat to over three lakh human lives, ecology and biodiversity of the Chittagong Hill Tracts (CHT). The department of environment banned levelling hills in 2005.

Mudslides triggered by monsoons killed at least two people and injured 20 others at sadar and Lama upazilas of Bandarban district in the last three days. Besides, mudflows have caused extensive damage to many houses in the CHT.

Earlier on Monday, a series of landslides across the port city left at least 123 killed and scores injured.

Illegal hill clearing is common in almost all the 28 upazilas of Khagrachhari, Rangamati and Bandarban, the forest office sources said.

Local influentials teamed up with a section of crooked government officials have levelled off a vast expanse of hilly areas to build houses, business centres and other structures, they added.

In Khagrachhari district, Shalban, Comilla Tilla, T&T Building area, Sabujbagh, New Police Lines, Panchmile, DC Hills, Jail Hills, Roads and Highway Resthouse Hills, Khagrachhari College Para, Tetultala and No-1 Kadamtali are the areas where denuding and razing of hills are rampant.

Besides, Barkal, Subolong, and Rajasshali in Rangamati and Balagata, Alikhong, Ruma, Dabrukhyong, Bus Stand area, Alikadam, Kalaghata and Betchhari areas in Bandarban have long been subjected to the illegal practice.

Some government establishments on the hillsides are dangerously exposed to rain-induced cave-ins.

Environment activists and journalists have filed several general diaries with the local police stations against hill cutting. But the administration has yet to take measures to protect the high lands from depletion.

Bangladesh Environmental Lawyers Association (Bela) last year issued legal notice to secretaries of the environment and forest, land and public works ministries, calling on them to act immediately against hill cutting but to no effect.

The same year it also issued notice to divisional commissioner of Chittagong, deputy commissioner of Khagrachhari, environment department offices in Dhaka and Chittagong, superintendent of police and Dighinala upazila nirbahi officer in Khagrachhari.

But nothing fruitful came as the hill-cutting syndicate comprising local political leaders, government officials and law enforcers continued business as usual, raising the spectre of landslides and flash flood in the CHT, said Fazle-Elahi, president of Global Village, an NGO based in Rangamati.

The syndicate supplies soil to the districts and also to the port city and adjacent areas at the expense of local hills, he added.

Those soils are used to fill up canals and lowlands chosen as construction sites for houses and markets.

"Supplying soil has become a profitable business as it needs only a little investment. A truckful of hilly soil sells at Tk 500," Abdul Haq, a trucker from Banderban said.

Besides, the hill cutting accounts for diminishing soil fertility in the districts, observed Additional Deputy Commissioner (Rev) Tapan Kanti Ghosh of Khagrachhari.

Divisional Forest Officer in Bandarban Abdul Mabud said the CHT is in grave danger of chain mudslides. An integrated approach is necessary to avert situation similar to Monday's.

Contacted, Banderban Superintendent of Police Mohammad Abdul Kader too expressed alarm about the disaster that looms.

He however said they are taking steps to stop hill cutting following up complaints lodged by different individuals and organisations.