They also demanded punitive action against those involved in hill cutting activities. Hill cutting involves levelling hillsides to make room for building.

Taking the advantage of current political crisis, unscrupulous people have become active again and are cutting hills to grab lands, they said.

Jubo Nagorik Odhikar Jote and Green Voice jointly organised the rally in front of the National Museum at Shahbag in the city.

Despite a ban on such activities, the land grabbers are cutting hills and trees in different areas of Chittagong, Cox's Bazar, Sylhet, Mymensingh and Sherpur districts, depleting forest resources, said Alamgir Kabir, convener of the Green Voice.

He said about 35,000 acres of hilly areas in Chittagong have been turned into plains in the last 20 years due to rampant hill cutting.

Unscrupulous people in connivance with local political leaders and a section of forest officials have resorted to such activities in order to develop residential plots and also to collect soil, he said.

Even some government officials have developed residential plots on 51 acres of hilly areas illegally along Cox's Bazar bypass road recently, he added.

Mohammad Shahidullah, convenor of the National Committee to Protect Oil, Gas, Mineral Resources, Electricity and Port, said environmentalists have long been raising their voice against hill cutting, but the authorities have a turned a deaf ear.

He demanded proper enforcement of laws protecting the environment.