this is how section 3 of ORDINANCE NO. 043-02 Series of 2002 or the comprehensive anti-smoking ordinance of davao city defines smoking:

"Smoking refers to the lighting and/or puffing of any lighted cigarette, cigar, tobacco or any other kind, form or type. Possession of any lighted cigarette, cigar, tobacco and the like within the prohibited areas for smoking shall constitute a prima facie evidence as an act of smoking prohibited under this Ordinance."

this means e-cigarettes are allowed since they are not lighted.