Zhang Dejiang, the top Chinese official responsible for Hong Kong affairs, conducted a visit to Hong Kong amid rumours of organised pro-democracy protests; however, there was an increased police presence and numerous arrests were made. Wuhan Tianhe International Airport introduced single-sex security lanes in order to improve the flow of passengers through security checkpoints. Tsai Ing-wen was sworn in as the new president of Taiwan, calling for increased dialogue and positive communication with officials in Beijing. On 8 May, a landslide in Fujian province killed 22 industrial workers. Ling Jihua, former aide to ex-president Hu Jintao, was formally charged with corruption. During the opening session of the Scottish Parliament in May 2016, Willie Rennie, leader of the Scottish Liberal Democrats party, questioned the human rights record of two Chinese firms involved in a Scotland-China investment agreement. The United States (US) continued to conduct freedom of navigation exercises in the South China Sea to maintain access to important sea and air routes. The Chinese economy continued its slump as lower figures than predicted for both imports and exports were recorded for April 2016. The US announced that it increased import duties on Chinese steel makers following accusations that they were selling products below market prices.