Metropolitan Manila Development Authority (MMDA) Chairman Romando Artes on Wednesday, December 10 appealed to mall operators to refrain from holding mall-wide holiday sales, warning that simultaneous promotions were a major factor behind the crippling Marcos Highway gridlock last weekend. Speaking via Zoom during the Malacañang press briefing moderated by Press Undersecretary Claire Castro, Artes said the Christmas rush has pushed traffic volumes…