Premier Li Keqiang said Wednesday China will set up a special fund to pool together the country's finest scientists to find the "unique" causes of smog that frequently hovers over north China's winter skies.

China will fight and win the battle against smog but it takes time, Li told a press conference held after conclusion of the annual legislative session.

He said scientists told him during the session that they have not yet fully understood the causes of the winter smog in north China, which are quite unique in the world.