The trend gives rise to the threat of water-logging and ecological imbalance.

There is a legal provision of imprisonment for five years and fine up to Tk 50,000 for filling up any water body in the city area without the approvals of Rajshahi City Corporation (RCC) and Rajshahi Development Authority (RDA).

But the RCC or RDA authorities did not take action against anyone so far.

There existed more than 4,000 ponds in the municipal areas in the '60s and 3,000 ponds in early '70s, a RCC census said. adding the number went down to as low as 600 till 2000.

Over the last five years, more than a half of them were filled up, said RCC sources.

During the current dry season, ponds are being filled up in many places including the posh areas of Baliapukur, Ambagan, Ghospara, Chandipur, Mohishbathan, Sagarpara, Talaimari, Laxmipur and court area.

With the increase of population in the metropolis, lowlands and water bodies were filled up for residential and commercial use.

In many cases, the influential persons filled them up to build markets on it.

The RDA authorities, admitting the allegations, said the rules to stop filling of water bodies had many loopholes and could not be applied against the violators of law.

However, the RCC officials said RDA is responsible for checking the practice. If they (RDA) seek any help from us, we are ready to help them', said RCC Chief Executive Officer.

Prof Sarwar Jahan of the Environmental Science Institute of Rajshahi University said the water reservoirs are essential for maintenance of ecological balance. 'We should stop people from filling up water bodies,' he said further.

Fish production has declined to a great extent over the last decade while ecology in the area degraded because of filling up of ponds, he added.