391(1) stipulates that the level, direction, width and means of drainage of every private street, the kind and number of trees to be planted and reared besides such streets and the height and means of drainage and ventilation of, and access to all buildings to be erected on such land or on either side of, such street shall be fixed and determined by the Commissioner subject to such general directions as the Standing Committee may give in this behalf, from time to time, with the general object of securing sanitary conditions, amenity and convenience in connection with laying out and use of any neighbouring lands, and also with the object that the proposed private street may not conflict with any arrangements which have been made or which are, in the opinion of the Commissioner, likely to be made for carrying out any general scheme of new streets or of improvement of existing streets in the locality. Section 394 provides that, if any private street be not levelled, metalled, flagged or paved etc to the satisfaction of the Commissioner, he may, with the sanction of the Standing Committee and by written notice, require the owner or owners of the several premises fronting or adjoining the said street or other means of access or abutting thereon or to which access is obtained through such street or other means of access or which will benefit by the works executed under this Section, to carry out any one or more of the aforesaid requirements in such manner as he may direct.