Millions of people in the Yangtze delta are living without drinking water, in power shortage and surging inflation, as the Yangtze river is experiencing the worst drought in 50 years.

Shanghai’s government promised on Thursday that the 23 million residents would not face shortages at home, after the city's electricity utility warned that some stores and factories may have to close in the hottest days of summer to limit demand.

The hydro-electric generation for irrigation, drinking and eco-system support is being diverted for dams to release 5bn cubic metres of water from Wednesday to June 10.