In February, 50 million litres of acidic waste from a tailings dam run by Sino-Metals Leach Zambia and NCF Africa Mining – subsidiaries of Chinese state-owned firms – contaminated the Kafue River, near the city of Kitwe.

The disaster destroyed farmland and has prompted nearly 200 Zambian farmers to file an US$80 billion lawsuit against the companies, demanding compensation and long-term environmental remediation work.

Li’s visit also follows China’s agreement to provide US$1.4 billion to overhaul and run a dilapidated 1,860km (1,155-mile) railway that connects Zambia’s copper belt region to the Tanzanian port of Dar es Salaam on the Indian Ocean – a key alternative to South African ports.