13.—(1) Where an order under Article 12 comes into operation, the district council which made the order shall, for the purpose of supplementing such information as it has in relation to the designated area in question, cause an assessment to be made of—
(a)the quality for the time being, and the likely future quality within the relevant period, of air within the designated area to which the order relates; and
(b)the respects (if any) in which it appears that air quality standards or objectives are not being achieved, or are not likely within the relevant period to be achieved, within that designated area.
(2) A district council which is required by paragraph (1) to cause an assessment to be made shall also—
(a)prepare, within the prescribed period, a report of the results of that assessment; and
(b)prepare, in accordance with the following provisions, a written plan (in this Part referred to as an “action plan”) for the exercise by the council, in pursuit of the achievement of air quality standards and objectives in the designated area, of any powers exercisable by the council.
(3) A district council shall, before finally determining the content of the action plan, send to the Department and each relevant authority—
(a)a copy of any order (together with any map or plan referred to therein) made by it under Article 12;
(b)a copy of the results of the assessment mentioned in paragraph (1);
(c)a copy of the report mentioned in paragraph (2)(a); and
(d)a copy of the proposed action plan.
(4) Where a relevant authority has received the proposed action plan under paragraph (3), it shall, within the relevant period, submit to the district council—
(a)proposals for the exercise (so far as relating to the designated area) by the authority, in order to comply with or in pursuit of the achievement of air quality standards and objectives, of any powers exercisable by the authority; and
(b)a statement of the time by which it proposes to implement each of the proposals
(5) Subject to paragraph (8), an action plan shall, in addition to the measures proposed by the district council under paragraph (2)(b), also include a statement of—
(a)the proposals submitted pursuant to paragraph (4)(a);
(b)the times set out in the statement submitted pursuant to paragraph (4)(b);
(c)the time by which the district council in question proposes to implement each of the measures proposed by it comprised in the plan.
(6) Subject to paragraph (7), a district council may from time to time revise an action plan.
(7) Before a district council revises an action plan under paragraph (6), it shall provide the Department and each relevant authority with a copy of the proposed revision, and paragraphs (4) and (5) shall apply to a revision of the action plan as they apply to the making of the action plan.
(8) Where a relevant authority disagrees with a district council about the contents of a proposed action plan or revision of an action plan—
(a)either of them may refer the matter to the Department;
(b)on any such reference the Department may confirm the council’s proposed action plan or revision of the action plan, with or without modifications (whether or not proposed by the authority) or reject it and, if it rejects it, it may also exercise any of its powers under Article 14; and
(c)the council shall not finally determine the content of the action plan, or the revision of the action plan, except in accordance with the Department’s decision on the reference or in pursuance of directions under Article 14.
(9) When the content of the action plan or the revision of the action plan is finally determined, the district council shall send a copy of the action plan or revision of the action plan to the Department and each relevant authority.