Japan's trading partners are pressuring Japan to make its trade policies clear.

Literal

Trade partner-country [topic-は] trade policy [object-を] make-clear [quotative-と], Japan [to-に] pressure [object-を] applying-is.

明確にせよ uses the classical/formal imperative せよ (alternative to しろ) of する. と marks the quoted demand. 圧力をかける ('to apply pressure') is a fixed idiom for political/diplomatic pressure. A news-register economic statement.