The MWA explained that the job to trim the trees near Dhurakij Pundit University was done in accordance with the Water Supply Canal Act 1983, in order to maintain the waterways that funnel raw water to tap-water facilities.

The agency said it had asked local bodies to trim the trees for fear tall trees could fall and block the waterway and affect the Bang Khean tap-water facility.

The MWA apologised for what happened and said it would ask the local bodies to stop trimming trees and appropriate response measures would be discussed.

The Thailand Urban Tree Network said the trees were trimmed too much.

It said a network member discovered that had been done on April 6 and photographic evidence was taken.

The group urged people to remain vigilant in relation to the issue, with lush trees welcomed when trying to minimise the heat.