Section 48. No urban renewal project shall be undertaken until (1) a public hearing relating to the urban renewal plan for such project has been held after due notice before the city council of a city or the municipal officers of a town and (2) the urban renewal plan therefor has been approved by the municipal officers and the department as provided in this section.

Whenever a public hearing on an urban renewal plan is held, notice thereof shall be sent to the Massachusetts historical commission together with a map indicating the area to be renewed.

Whenever the urban renewal agency determines that an urban renewal project should be undertaken in the city or town in which it was organized, it shall apply to the municipal officers for approval of the urban renewal plan for such project. Such application shall be accompanied by an urban renewal plan for the project, a statement of the proposed method for financing the project and such other information as the urban renewal agency deems advisable.

Every urban renewal plan approved by the municipal officers shall be submitted to the department together with such other material as the department may require.

The department shall not approve any urban renewal plan unless the planning board established under the provisions of section seventy or eighty-one A of chapter forty-one for the city or town where the project is located has found and the department concurs in such finding or, if no planning board exists in such city or town, the department finds that the urban renewal plan is based upon a local survey and conforms to a comprehensive plan for the locality as a whole. The department shall likewise not approve any urban renewal plan unless it shall have found (a) the project area would not by private enterprise alone and without either government subsidy or the exercise of governmental powers be made available for urban renewal; (b) the proposed land uses and building requirements in the project area will afford maximum opportunity to privately financed urban renewal consistent with the sound needs of the locality as a whole; (c) the financial plan is sound; (d) the project area is a decadent, substandard or blighted open area; (e) that the urban renewal plan is sufficiently complete, as required by section one; and (f) the relocation plan has been approved under chapter seventy-nine A.

Within sixty days after submission of the urban renewal plan, the department shall give written notice to the urban renewal agency of its decision with respect to the plan. If the department shall disapprove any such plan, it shall state in writing in such notice its reasons for disapproval. A plan which has not been approved by the department when submitted may be again submitted to it with such modifications, supporting data or arguments as are necessary to meet its objections. The department may hold a public hearing upon any urban renewal plan submitted to it, and shall do so if requested in writing within ten days after submission of the plan by the urban renewal agency, the mayor or city council of the city or selectmen of the town in which the proposed project is located, or twenty-five or more taxable inhabitants of such city or town.

Any provision to the contrary notwithstanding, when the location of a proposed urban renewal project has been determined, the urban renewal agency may, without awaiting the approval of the department, proceed, by option or otherwise, to obtain control of such property within the urban renewal project area as is necessary to carry out the urban renewal plan; but it shall not, without the approval of the department, unconditionally obligate itself to purchase or otherwise acquire any such property except as provided in section forty-seven.

When the urban renewal plan or such a project has been approved by the department and notice of such approval has been given to the urban renewal agency, such agency may proceed at once to acquire real estate within the location of the project, either by eminent domain or by grant, purchase, lease, gift, exchange or otherwise.