Local authorities means the Pakistani government.
Rawalpindi is located next to Islamabad, the national capital, meaning that the national government must have been aware of the event and allowed it. The Ahmadiya mosque had been functioning for over fifty years. There was no dispute that the place belonged to the Ahmadiyas. It was not an issue of property. The issue was that orthodox mullahs are opposed to the existence of any Ahmadiya mosques in Pakistan, not that they were disputing the location of one of them.