The Kolkata Municipal Corporation (KMC) on Wednesday started excavating a pond in Jadavpur that had long ceased to be a water body and turned into a garbage dumping ground for residents.

Nearly 8ft-deep waste had to be cleared before the water could was visible again. Residents said people had been throwing waste in the water body, which measured about 8.5cottahs, for nearly two decades. Over the years, layers of waste piled on and at one point it was impossible to recognise the plot as a water body.

The excavation comes a little over a month after the collapse of an illegal under-construction building in Garden Reach, that came up on a plot, a portion of which was a water body.

There are scores of complaints of “attempts to fill up water bodies” filed with the KMC. A KMC official said that the civic body has filed 150 FIRs against “attempts to fill up water bodies” in the last two years.

Wednesday was the first time the KMC went beyond merely registering an FIR and started restoring a pond to its old status. The work in Jadavpur’s Jorabagan Road was relatively easy because no builder had yet started filling up the plot to raise a building.

“This is the first in a line of at least seven to eight more water bodies that will be restored immediately. We will keep taking up one after another,” mayor Firhad Hakim told Metro. “We will recover the cost of restoration from the owner of the water body in such cases where the owner is known to us,” Hakim added.

The ownership of the pond in Jadavpur that the KMC started restoring on Wednesday was not known to the civic body. The mayor said the KMC has to bear the cost in such instances.

A KMC official said ponds in Behala and near Dum Dum were among those identified for restoration.

“We examined satellite maps available with us that are about two decades old and these maps showed this pond measured about 8.5 bighas then,” said the official.

The map he was referring to was a pan-Calcutta survey by the National Remote Sensing Agency. The maps of the survey were published in 2004.

Metro reported recently about scientists pointing out that the filling up of water bodies, loss of green cover and diminishing open green spaces were making the heat more unbearable. The city is in the grip of a long phase of extreme heat and above-normal temperatures. Studies have shown urban areas with more concrete construction are hotter than peri-urban or rural areas with more green and blue cover.

Water bodies and green cover have a cooling effect, while concrete and built-up areas trap and radiate the heat back.

The KMC aims to wrap up the Jadavpur pond restoration by the end of this week. A coconut tree has come up on the plot. Civic engineers said they were trying to keep it and restore the water body.

Weeds and a banana tree on the plot would be cleared.