Unbridled construction activities in eco-sensitive areas with natural water flow have a devastating effect and lead to natural calamities such as those seen in the recent floods in Tamil Nadu, Kerala and Uttarakhand, the Supreme Court has said.

‘‘Expert opinions suggest that the devastating floods faced by Uttarakhand in recent years and Tamil Nadu this year are immediate result of uncontrolled construction activities on river shores and unscrupulous trespass into the natural path of backwaters,’’ a Bench of Justices Arun Mishra and Navin Sinha observed in a recent order.

The observations are part of its direction to the authorities in Kerala to demolish certain apartment blocks situated in ecologically sensitive areas at Maradu panchayat within a month. In a detailed order published lately, the court declared the permission given by the panchayat authorities for their construction as ‘‘illegal and void.’’

‘‘We take judicial notice of recent devastation in Kerala which had taken place due to such unbridled construction activities resulting in colossal loss of human life and property,’’ the Supreme Court observed.

It said the area in which the construction was carried out was part of tidal influenced water body and strictly restricted under the provisions of the Coastal Regulation Zone (CRZ) notifications.

‘‘Uncontrolled construction activities in these areas would have devastating effects on the natural water flow that may ultimately result in severe natural calamities,’’ the Bench said in the order.

The Coastal Zone Management Plan (CZMP) has been prepared to check these types of activities and construction activities of all types in the notified areas.

Under Section 3 of the Environment Protection Act, 1986, the authority is empowered to deal with environmental issues relating to the notified CRZ areas. Construction activities in the notified CRZ areas can be permitted only in consultation with and concurrence of the authority.

‘‘It is the binding duty of local self-governments to forward application for building permission to the authority along with the relevant records,’’ the court said.

The significance of CRZ notification in the interest of protecting environment and ecology in the coastal area and the construction raised in violation of the regulations cannot be lightly condoned, the Bench quoted from past judgments on the issue.