25. — (1) For the purpose of preventing or limiting air pollution, the Minister may, by regulations, prohibit or restrict the emission into the atmosphere of smoke from any premises.

(2) Without prejudice to the generality of subsection (1), regulations under this section may—

(a) specify the premises to which the regulations apply,

(b) specify the kind of smoke to which the regulations apply,

(c) prohibit, either absolutely or subject to specified exceptions, the emission of smoke from specified premises at specified times or periods,

(d) exempt, subject to or without conditions, from any of the provisions of the regulations emissions of smoke from specified premises for specified periods,

(e) prohibit or restrict, subject to such exceptions as may be specified, the burning of straw, waste or any other substance at such premises or at such times as may be specified.

(3) In any prosecution for a contravention of this section or of regulations made under this section, it shall be a good defence to establish that—

(a) the best practicable means have been used to prevent or to limit the emission concerned, or

(b) the emission concerned was in accordance with a licence under this Act, or

(c) the emission concerned was in accordance with an emission limit value, or

(d) the emission concerned was in accordance with a special control area order in operation in relation to the area concerned.