Water from a construction site in Pietà and dumped into the Msida marina on Thursday morning was clean seawater, according to the contractor responsible for the site.
"It was not dirty water; it didn't contain drainage or anything like that," contractor Joseph Portelli said.
Portelli said that seawater had seeped into a hole the waters had just dug, which would eventually serve as the base of a tower crane.
He immediately pumped the water into a culvert cover, and back into the sea.
"The water was mostly clear, and only at the end was there some residue," he said, adding that any residue left on the pavement was cleaned up.
Visiting the site on Thursday morning, Times of Malta noticed the water immediately in front of the construction site had turned slightly milky white.
Contacted for a comment, Pietà mayor Zoya Attard said she would bring the issue to the attention of the police and the local council.
"Actions that pollute the seas and our surroundings are condemnable," she said.
Questions were also sent to the Environmental Resource Authority.