become e e of t the biggest d developersd financiers of coal-fired power plants abroad, ranging from vietetnam to africica to indon. this is a very harmful development. repoporter: domestically, , te are still many problems to overcome, like feeding energy into the power grid. currently, large amounts of energy are wasted. zhang quan is aware of the contradidictions.. does he think china can play a leading role in climate protection? the engineer from ningxia is certain it can. he says he's surrounded by proof of it every day. host: today's global snack comes from tunisia. enjoy. reporter: tunis -- capital and political center of tunisia. some two million people live in the greater metropolitan area, in a city that's both modern and traditional. in the city's center is the sahfa toun, named after the snack made here. the snack bar is an institution, with only one thing on the menu. safha toun is made from olive oil, egg, a lot of garlic, and harissa -- a hot paste made from chili, cumin, coriander seed, garlic, salt, and olive oil. with that, you get tuna and a choice of toppings like cheese o