The order was issued on a PIL by a division bench of the High Court, comprising Chief Justice Barin Ghosh and Justice Sarvesh Kumar.
The court has also sought a reply from the state government detailing methods by which it plans to impose the ban on such constructions.
The PIL was filed by a Rishikesh resident, challenging an earlier government order which though putting a ban on construction activities within 100 metre radius of the Ganga, exempted temples, dharamshalas and mutts from the ambit of the order.