Stung by the impact of the financial crisis, the hilly city of Yunfu in China’s southern Guangdong province decided in 2009 it was time for a makeover. Known over hundreds of years for producing delicate stones for arts and crafts, the city had few modern industries apart from consumer appliances.

So officials decided to lop the top off the surrounding hills and build a 13.4 sq km industrial park focused on fuel cells — a rival technology to internal combustion engines and electric batteries.

Attracted by generous government subsidies, a whole suite of companies covering the supply chain have now set up in the park, which is producing hundreds of buses and small trucks using fuel cells that run on hydrogen gas. So successful has it been that local officials now plan to flatten two more hills to create a neighbouring vehicle manufacturing plant and a chemicals facility.