Beijing launched a sweeping investigation into US efforts to block imports of Chinese clean technology on Friday. China’s Ministry of Commerce announced the probe into “trade barriers on green products” alongside a separate trade investigation in the lead-up to an expected visit to Beijing by President Donald Trump in May. By kicking off its investigation — itself a response to US probes — China is preparing a legal basis for retaliation against any new US duties after the majority of Trump’s previous tariffs were struck down by the Supreme Court, experts said. The trade in green goods is “an obvious…