The Council shall at all times control the distribution of space in, over, under or across all streets or public grounds occupied by public utility fixtures. All rights granted for the construction and operation of public utilities shall be subject to the continuing right of the Council to require such reconstruction, relocation, change or discontinuance of the appliances used by the utility in the streets, alleys, avenues and highways of the city, as shall in the opinion of the Council be necessary in the public interest.