New Delhi, June 6 -- Fresh signboards marking Delhi's environmentally sensitive "Zone O" have appeared across several Yamuna floodplain localities, triggering concerns among residents who fear the exercise could precede demolition drives against unauthorised constructions.

Officials of the Delhi Development Authority (DDA), however, said the exercise is aimed at demarcating the protected zone, raising public awareness and preventing further encroachments, adding that no demolition drive has been planned at present.

According to officials, the signboards are being erected across areas falling within Zone O, which covers large stretches of the Yamuna riverbed and floodplain. The exercise follows directions issued in connection with ongoin...